Doesn't really prevent accounts being sold, and then claimed back though. I'm not sure what the forums stance on selling accounts, and who the rightful owner is, but I assume that they would look for information that might indicate that the account was sold, and see if the credential changes link up to that too.
An automated method to claim back your account could severely reduce account sales. Who's going to pay hundreds of dollars for an account, knowing the previous owner can claim it back at any moment?
Losing your bought account will just become an occupational hazard.
I also wonder what will happen to those users who can't sign a message posted here because the hacker deleted it but the address can still be found archived online or on one of the bitcointalk mirrors etc. There's also the issue of those who don't have a bitcoin address but can sign one from an alt coin wallet. I'm going to assume theymos' auto-recovery system will be bitcoin only?