I think it really would be nice if you started playing Achievment Unlocked 2 at your house, then continued playing where you left off at his house (of course on your account).
Yes it works shayneii. You can also email it to the other comp, or host it somewhere like on a googledoc. However, the thing you're saying ichigo is already being used in some games, like exit path or colony or armor mayhem. I believe all the games by AG developers will use that in the future.
That's not really how flash games work, OP. In order to do that, you would have to do what Shayne2 suggested, which is find "cache.armorgames.com" and the specific "achievement unlocked 2" save file. If you take the achievement unlocked 2 save file, put it into a flash drive, and stick it into another hard drive, you will be able to play your save at another person's house. You cannot really suggest something AG has no control over :-/
No it'd be much harder. Saving data on your computer with shared local object is extremely easy for flash developers, saving on your AG account requires a lot of website interaction. Trust me, using .sol files is much more simple.