Regional unavailability is about as old as gaming itself, although it's grown less acceptable in the age of the Internet.

I am not really saying I like it, but here is the thing: every company is already doing business like that.
Think about it: How often are we told what save-model a game is going to use before it is released? We find out a few weeks before release in a preview, if that. Since this DRM is heavily based on the save-model...

How often has the save model (for a single player game) been affected by the DRM? Never, as far as I know. That's why they need to provide info.

That is just it, one of the (many) big problems with this is that the save model impacts how the user experiences the DRM.
But describing the save model is hell. Plus, I have a sneaking suspicion that one reason we don't hear about it is because it ends up being finalized very late in the (real) beta testing process (not the pre-order exclusive demo).
Let's say you have a game like Far Cry 2 where you can save whenever you want, or when you sleep in your safehouse(s). Explaining that, you either convince people that they need to save every five seconds, or you make people wonder how often they use safehouses and the like (I use them only when I need to recharge my buddy or grab some ammo :p).
Now let's say you have a game like AC2 which apparently uses checkpoints. Then you need to explain how far apart the checkpoints are.
Or you have something like the earlier Tom Clancy games where there were no quicksaves, and having to respawn/reload was pure hell.
This is more a problem with the DRM model itself. But honestly, I don't fault Ubi for not wanting to open this can of worms. And, when you get right down to it, it isn't a massive issue in the grand scheme of things. It still boils down to "reload your most recent save".

So it looks like Steam wasn't enough for Ubi, they want to go one step higher, in every negatively possible way.
Oh well, the bottom line will hopefully prove them wrong, unless people are sheep.
Wait...oh damn.

If they were a little smart (I know it's unlikely but let's pretend) they could implement secondary "savestate" like system that will save locally where you were when the connection was lost and allows you to continue from the exact same spot as soon as the connection is restablished. Similar to what happent when you close/reopen your DS or do a soft powerof of your PSP.

Gundato, I see what you're saying, but "It's too complicated" isn't a good enough excuse to tell the potential buyer to "figure it out for yourself".
In the examples you give, it would be enough to say "Game A will reset you to your latest checkpoint. Game B will reset you to your last manual (or auto, whatever the case may be) save. Game C will restart you right where you left off." If questions about more detail are too much for them to handle (such as how often are there checkpoints in the game, or can you manually save anywhere in the game), then I guess they 're not real interested in promoting their product.
As a potential customer, I can't accept that a publisher is not willing to provide me with at least that much information, but instead are just waving their hands at me to basically figure it out for myself. I'm sorry, but that kind of dismissal by any company is not a good way to get me to pick up their product on release day - or ever, for that matter.

Unfortunately not, it automatically synchronises saves regularly during your gaming session and there has been no mention of changing the frequency of the update or disabling it entirely. If your connection to the server is lost it will freeze the game until a connection can be re-established; for some games you will be able to resume where you left off while others will throw you back to the last checkpoint.

They were specifically asked by kotaku about the viability of the scheme for Australians where our broadband is far from universal and our bandwidth is regularly eaten by bunyips
http://www.kotaku.com.au/2010/02/ubisoft-explains-australian-drm-scenario/
in short they say: Don't worry about it, she'll be right mate!
Aside from the consistent speed progblem, the other important consideration is that not only are there many places where you still can’t get broadband (flats with a single phone line frequency split into several in much the same way broadband works are a notable example) but there’s the issue of caps & throttling.
Say your pervert little brother has wasted most of your monthly bandwidth downloading porn that you don’t like (probably those 2 girls and their cup). Because of this you go over your limit in the first or second week of the month and are capped which kills your single player possibilites since you no longer meet the speed requirements, you’re locked out of your single player game for 2-3 WEEKS until your limits reset and to top it all you don’t even have any good porn to entertain yourself with in the meantime.
That would induce 3 likely results, firstly you kill your brother, secondly you get pissed off with the company and not buy their stuff again, third you search for a way to prevent that situation happening again, perhaps bypassing the system entirely with some sort of download…
Maybe ubi are trying to explore temporal theory, this is like the start of a predestination paradox.
UbiExec1: "We've seen the future, the PC market is destroyed by piracy!"
UbiExec2: "What? Why would they pirate stuff if it will destroy the market?"
UbiExec1: "Oh there was some bullshit 'sticking it to the man because of restrictive business practices' excuse but they're pirates, who cares why they do things?"
UbiExec2: "Good point! We have to stop them"
UbiExec1: "Perhaps some kind of system that puts excessive restrictions on them..."

Assassin's Creed II is now available for pre-purchase on Steam. It is $59.99 and look at that.
3rd Party DRM: UBISOFT REQUIRES A PERMANENT HIGH SPEED INTERNET CONNECTION AND CREATION OF A UBISOFT ACCOUNT TO PLAY THIS VIDEO GAME AT ALL TIMES.
A PERMANENT HIGH SPEED INTERNET CONNECTION AND CREATION OF A UBISOFT ACCOUNT ARE REQUIRED TO PLAY THIS VIDEO GAME AT ALL TIMES AND TO UNLOCK EXCLUSIVE CONTENT. SUCH CONTENT MAY ONLY BE UNLOCKED ONE SINGLE TIME WITH A UNIQUE KEY. YOU MUST BE AT LEAST 13 TO CREATE A UBISOFT ACCOUNT WITHOUT PARENTAL CONSENT. UBISOFT MAY CANCEL ACCESS TO ONLINE FEATURES UPON A 30-DAY PRIOR NOTICE PUBLISHED AT http://assassinscreed.com
So funny.

"UBISOFT MAY CANCEL ACCESS TO ONLINE FEATURES UPON A 30-DAY PRIOR NOTICE PUBLISHED AT http://assassinscreed.com "
So, since single player requires you to be online, does single player count as an online feature that they can shut down with a 30 day notice?

PC Gamer has confirmed the unbelievable specifics of Ubi's new scheme.
"If you try to launch the game when you're not online, you hit an error message right away. So I tried a different test: start the game while online, play a little, then unplug my net cable. This is the same as what happens if your net connection drops momentarily, your router is rebooted, or the game loses its connection to Ubisoft's 'Master servers'. The game stopped, and I was dumped back to a menu screen - all my progress since it last autosaved was lost ... any time Ubisoft's 'Master servers' are down for any reason, everyone playing a current Ubisoft game is kicked out of it and loses their progress."
Short answer: yes.
This won't be the first time, either. Ubisoft once offered ad-supported free releases of a couple of their games as an experiment; you had to log into Ubi.com from the installer, and it could not begin installing unless the server said it could. One day they quietly pulled the plug and that was that. Just because Assassin's Creed II costs US$60(!) doesn't mean they are going to treat its players any better.

$60?
The worst DRM ever conceived?
Does Ubisoft want this game to fail on the PC?

So, anyone want to take bets on how long before a cracked copy of AC2 is made available? I'm putting the over-under at 3 days from release.