Okay. Now I'm confused.
I mentioned yesterday that I'd contacted someone who had apparently unfriended me on Facebook some time ago. On the basis that he appeared to have implied that he hadn't unfriended me, I sent him another friend request.
It appears that he has since deleted the friend request.
Either that, or Facebook is so screwed up that it has deleted the request for him.
Which puts me back to square one. I still don't know whether there really is a glitch in Facebook that unfriends people, or whether it's just a convenient excuse...
Or maybe its just me. :-/