Sufyan: You have been repeating weird ideas about exploitable bugs being intentional game design decisions. In fact, I think most of your topics on here, regardless of title, are about exploits you like. You think the skillbook bug is intentional, you think the histories bug is intentional, and this is the second time you bring up the serial killer scripting bug.
Why not just use console commands if you're so hell bent on cheating? Why go through all this trouble to boost your character?
KiNgBrAdLeY7: At least the tome thing works normally as intended. Basic patch hasn't "fixed" it... (At least yet)
Why on earth would you think this is anything less than an interface bug!? As intentional game design it makes little sense why it would work this way.
Let's look at the very first store you can encounter in the game; Trip's Pawnshop. Every time you load the level it spawns a basic inventory which includes two skill books. If you buy one, it is removed from the store inventory and a copy is placed in your own inventory. Next time you open the store interface it restocks, which gives you an opportunity to buy the same book and indeed the same items, again. Maybe this was intentional...
... except how things get weird when you start selling stuff. Let's say you sell another skillbook found elsewhere, close the store interface and open it again without leaving the level. Now the skillbook you just sold is part of the stock, and when you buy it, it is removed from the store and a copy is placed in your own inventory just like with the other two books. You can read it (expend it, really), then buy it again from the store and repeat as many times as you want,
but if you leave the level any items you sold to disappear forever. Does that make sense if we interpret it as intentional game design? No, it is a design flaw, an oversight. It is a side effect of how stores inventories are scripted in the game. It is a hack job.
You have to remember that computer games are just a lot of smoke and mirrors to give you the illusion of things being physical and logical. Your imagination tells you that a book is taken from the store and given to your character, but in reality it is just one set of data deleted and another unrelated set of data created. It is a visual trick on top of a sterile set of code without meaning and association. The way the code is handled is not intuitive in a real world sense, so it is extremely unlikely that the designers went out of their way to write a design document specifying precisely this strange logic. Stores are probably not supposed to be magical, items are probably not supposed to duplicate by some very awkward and strange logic. It was probably supposed to work more intuitively: Money and product exchanges hands, and in the moment of purchase this is definitely how the illusion plays out. The weird stuff happens when you close the store interface or leave the store level and it no longer operates on real world logic.