I made sure to design my RSVP cards where I could write in each guests name. Well, I made two lines on each RSVP card and if it was just one person we were inviting, I crossed the other line out.
Well, someone wrote Guest over one of the lines I crossed out. Didn't even give me a name.
I told my FI he could make the choice on whether to let the guest come since the person we invited is his friend. Seriously, the line was crossed out for a reason.