I don't think they perform an explicit auto log in to cancel your delete request but mis-clicking a like button (or clicking on a harmless LOOK AT THAT FUNNY CA

I don't think they perform an explicit auto log in to cancel your delete request but mis-clicking a like button (or clicking on a harmless LOOK AT THAT FUNNY CAT PICTURE-URL in an IM chat, etc) might trigger a log in. They certainly track you even if you're not logged in so who knows what javascript trickery they're up to to make logging in 'easier'.