On our RSVPs we put a line for people to write in the guest's names (we printed individual cards for everyone with their name already on it). I was putting responses into Excel today and had someone indicate they were bringing a guest, with no name. I figured this would happen eventually, but hadn't yet made a contingency plan for it.
I don't know why, but I'm baffled by this situation. How do I make his guest a place card? Where do I put it in the alphabetical list? Do I just make a "Guest" one that goes behind his on the place card table? What are you planning in this situation?