Check out this leaked copy of the instructions Yahoo! sent to managers for conducting their 1,500 layoffs last week (courtesy of Valleywag).
There's much to cringe at here, but I think the worst is this: "Yahoo! will not ask for reimbursement from the employee on any repayment obligations (relocation, sign-on bonus), provided the employee signs the Supplemental Release."
So apparently if someone chooses not to sign the release (which, for those who haven't had the lovely experience of dealing with layoffs, is a form releasing the company from any legal claims, generally required to be signed before severance pay is released), they'd need to repay relocation expenses? After getting laid off. Lovely.
I'm (sometimes) sympathetic to businesses that need to conduct layoffs. It sucks, and sometimes it's unavoidable. But it's probably the most important time to go out of your way not to be an ass. Yahoo! forgot.