I mean seriously couldn't come up with it at all? Hopefully it wasn't during the act, but rather much much later when you ran in to them.
Oh hell yeah! I've probably even fucked someone without knowing their name (at the time).
Oh yes, I do have a sexy admin and I always forget her name when I try to fill out the bankwire for her salary. Must be her sexy eyes!
All the time. I'm terrible with names. It can be quite embarrassing, especially when someone remembers your name, but you can't remember theirs. I'm very good with faces, but names are my Achilles heel.
Always, it doesn't help that I have to remember a lot of people due to work.