That's a tricky situation, and I hope it never happens. Ultimately, it's a bit of a breach of your privacy, isn't it? They aren't your friends, really. I'd say

That's a tricky situation, and I hope it never happens. Ultimately, it's a bit of a breach of your privacy, isn't it? They aren't your friends, really. I'd say that I don't have one. (This would mean giving them a different email than the one I've got my Facebook account set-up with.) If I'm forced to provide one, I'd make a new one and only add them as a friend. (However if you do accept them as a friend on your real account, it'd be simple to set the privacy options to give them a customized view of your profile.)