Btw, @DanHulme: May I ask you to take a look at android.stackexchange.com/a/51458/16575 and see if I've got things right? Took me about two days to dig into that account-managing stuff :)
My answer is not nearly as good as yours on using accounts, but I hope I was able to explain the permissions involved...
Hm, and I wonder whether @Flow took that "official warning" and didn't fly to Egypt? Still seeing his avatar here in chat :)
Not correct? I understood the (systems) account manager as a kind of "supervisor", and the one who really executes any actions. Kinda "SuperSU for accounts"?
@DanHulme Yes, that's what i understood. Furthermore, as I understood, the AccountManager also takes care that e.g. the Dropbox app does only deal with Dropbox accounts (to put it into easy terms)?
@DanHulme Yeah, see that even with normal web pages ("log in with Google" etc.) :)