Personally, I see this thing not as cheating, but rather as clever (ab)use of the game's mechanics.

Also, it's the sort of reason why I would prefer to play the classic version of this particular game, and would play it *without* the fixpack. (Now, if the fixpack would allow me to apply only critical fixes (like fixes for bugs that could crash/softlock the game or make sidequests unclearable) and not apply things that "fix" many of the quirks and "exploits" of the game mechanics, then I would consider it, but as is I do not. For reference, when I used the Morrowind Code Patch, I deliberately unselected the "fix" that makes it so that blindness effects lower accuracy instead of raising it.)

I disagree on the "not cheating" part, but agree on the "clever" part ;)

I never (willingly) use exploits in my games, I don't like the idea of it. But it's nice that other people like you do play with them, because I love learning about quirky behaviours in games.

I cleave to a fairly similar stance, although for me player-installed mods are fair game, since you have to go out of your way to acquire them and you know what you're getting into. In general I divide such issues into Bugs, Exploits, Min-Maxing or Cheats.

Bugs are issues where the game is not functioning according to the rules, whether as a result of developer error or deliberate player action. An example might be, for instance, casting a spell from a Wand while the game is paused, but if the player swaps out the Wand in inventory before unpausing the game, it casts the spell from the old Wand, but it does not deplete any charges. Since Wands are always meant to deplete a charge when used, this is an obvious bug and should be fixed.

Exploits can partially fall into the first category if they make use of a bug, but I also categorize exploits as players making use of NPC behaviour that, logically, they should not be doing. Examples would be the classic BG1 Drizzt cheese method of dismissing your party members in such a way so that they all surround Drizzt, and then attacking Drizzt with ranged weapons, who will then simply stand in the middle doing nothing as he can't walk through the neutral former party members. An alternative example might be casting a Cloudkill spell into a room, then shutting the door, upon which the enemies will happily sit in the Cloudkill spell until they die. In both cases, it's obvious that the strategy would not fly in a tabletop game. However, I don't necessarily think that exploits need to be fixed, as they typically require deliberate action on the player's part to achieve and players who crave a proper encounter (like defeating Drizzt in a fair fight) can simply not make use of these exploits. The experience is limited to the player's own game.

Min-Maxing is a bit of a tricky subject, since I know there are players for whom min-maxing is a source of great enjoyment. (The caveat of course is that one person's min-maxing might also mean another player's complete disempowerment. I've played in tabletop games where min-maxers basically made themselves SO powerful that the non-min-maxers were basically reduced to being window dressing in encounters.) There are certain combinations of classes/spells/items that are borderline broken, and that, if I were the DM at the table, would outright ban from use for being too disruptive to the game. However, that's not my call to make here, so my stance is that it should adhere to whatever the current rules+errata is for the ruleset in question.

Cheats are very similar to exploits, except that they are exploits that go above and beyond intended game behaviour, such as giving all of your characters 25 in every stat, 100% Magic Resistance, etc. Much like exploits though, in a single-player game I feel that you can do whatever you want to alter your own game experience, as long as it doesn't affect anyone else's.

While I clearly have a broader definition of "cheating" than both of you do, I want to avoid an easy misunderstanding: I do no see cheating as a bad thing that people should stop to do.
Everyone cheats at some point or another in some games, and as long as it improves the game enjoyment it should be done ;)

To use a short definition, I’d say I would call cheating any time the player is not playing by the rules the designers intended. "Intended" is the key word here, as this is not always what is actually implemented, due to bugs.

I would argue that obvious bugs shouldn't always be fixed. In particular, I can cite a couple examples of this:

1. If the game is balanced around a bug, fixing the bug can negatively affect the balance of the game unless the game is rebalanced around it. For example, Final Fantasy 5 has a bug where weapons whose damage is supposed to be based of both Strength and Agility aren't as strong as they should be; only the least significant byte of (Agility * Level) gets used. Fixing this bug has the effect of making daggers significantly stronger than swords, which feels rather strange. (You can see a bit of this in vanilla FF5; the Chicken Knife uses the *correct* damage formula, and as a result is much stronger than most weapons with comparable attack power.)

2. Games that are based around player-created content (see Unlimited Adventures, Neverwinter Nights, and even something like Mario Maker) can end up with content that is based around the bug. If the bug is fixed, you can break player-created content that relies on it.

From a single-player standpoint, if the game is played on the hardest difficulty, I think it's reasonable for the developer to expect the player to min-max. Min-maxing can be fun, but I also want a good challenge to test my min-maxed characters against. (Also, do note that, by definition, min-maxed characters have weaknesses. In 3.x, for example, anything that does damage to a character's dump stat has a sizable chance of killing or disabling said character. In a table-top setting, those can be used against min-maxers, or at least force their players to spend effort to minimize or cover up their weaknesses.)

What about when the game itself, or the enemies within the game, are not playing by the rules the developer intended? (Examples include the deliberate "cheating" that some BG series enemies do (like casting spells with ForceSpell(), which results in the spell being cast without being memorized and makes it not interruptible), and the Saw glitch in SaGa 1 (and many other bugs in that game's battle system code), which affects the enemies as well as you.)

I could also mention the idea of using a bug because that bug interferes with the strategy you really want to use. For example, in Final Fantasy Legend 2, it might sound like a good strategy to boost your Agility via SpeedUp so you can always heal before the boss acts, but that strategy gets stymied by an overflow bug in the initiative calculation; for one boss in particular, I have a strategy that relies on said overflow to make sure a certain party member always acts last. (Incidentally, the SaGa 2 remake fixed this particular bug, so I can now get my characters to consistently go before that boss with some preparation.)

There's also the situation where the game (or part of it) is so buggy that it's not even clear how it's intended to work; I encountered this in the game Centauri Alliance, where it's not clear how the cost of using the Ancient skill is supposed to be calculated. (It's actually calculated based on the slot the gun you're adding charges to is in your inventory, which does not make any logical sense.)

Hmm, those are good points. I personally feel that the bug should not have been allowed to get to this point in the first place, but it probably has its roots in poor weapon balance that's difficult to rectify without a complete overhaul of items/combat rules. (For a counter-example, two-handed weapons in D&D 3.X wind up way, WAY more powerful at high levels than one-handed weapons, due to the way that Strength bonuses for melee combat work, which ultimately results in a situation where no high-level warrior EVER uses anything but a two-handed weapon, because you'd be hamstringing yourself in terms of damage.)

But I do agree that invalidating a lot of player-created content due to a bug would be an unpleasant thing to do. If the bug is not especially game-breaking, it might indeed be better just to let things lie.

Hehe, yep. That's why my players in my tabletop games learned not to treat Charisma as a dump stat after they started encountering Mind Flayers with Ego Whip. ;) That said, I'm referring more to really extreme cases of min-maxing that make characters FAR more powerful than they have any right to be, to the point where they might start overshadowing other roles/classes. For instance, I had a Cleric/Mage player who Polymorphed himself into a Stone Giant, then layered on additional Clerical buff spells, magic items etc. until he became a near-unstoppable juggernaut in combat, practically displacing the party's Fighter player, who understandably was quite upset at having his role usurped.

What if someone were to mod BG2 so that Mind Flayers did Charisma damage instead of Intelligence damage? (Then again, it still makes no sense that you can die to a mind flayer eating the brain of your Mirror Image, but that's another story.)

You can, in fact, do this, but it takes some work. You'll need to dig through the weidu files before you install them and comment out the offending lines. The files are all text and are generally well-documented, so the biggest challenge is simply finding which of the several files the offending fix is in. You'll generally need to comment out the whole section.

Note that I haven't actually done this for the BG fixpack, but I commented out several things in the PST one and it was wonderful. Oftentimes big fixpack makers get overzealous and fix things that aren't actually bugs, and there's a number of instances of that in PST in particular. Things like the Patch for Purists for Morrowind (where the mod dev is extremely scrupulous about only including things that are uncontroversially actually bugs) seem to be quite rare by comparison.

Of course, there's the fact that sometimes I don't even want "fixes" for things that are actually bugs. As I have mentioned (don't know if in this topic), the Morrowind Code Patch, as one of its components (selected by default), makes it so that blindness lowers your accuracy instead of increasing it. Most people consider this to be an obvious bug, but I feel it gives things an interesting flavor that you don't find in bug-free games. (This isn't the only game I have seen this sort of bug in; SaGa 1 (on the Game Boy) has a bug where, when basic Strength based attacks are used, Agility is halved in the accuracy calculation *unless* the participant is blind; then again SaGa 1 is also the game with an instant-kill attack that works *only* if the target's defense is high, making it easier to saw apart a god than a lowly goblin.)

There's also the fact that, in my limited experiments of Icewind Dale: Enhanced Edition, I found that a fix for a certain exploit also blocked a legitimate strategy; if a Project Image gets killed, the caster can't summon another until the original spell's duration runs out or the caster is affected by a dispel effect.

(Also, I like having things like Armor of Faith stacking and Restoration on Simulacrums in; those seem like interesting strategies to me, considering that you do need to spend extra resources and turns to use those strategies. In fact, I looked through the spell list, and the only spells that stack in the original but not the EE that would be game-breaking if stacked are the Emotion spells from IWD (and you can still use multiple casts of Emotion: Courage for more healing).)