I am hosting a birthday dinner party for my SO at a restaurant for 20 close friends and family. I have reserved a private room, arranged for open bar and am covering the entire cost of the event, which is running about $110/pp.
Most guests have dutifully RSVP'ed, but I received a separate response from a friend's girlfriend asking if she could bring her cousin (who will be in town that weekend visiting friends). I asked whether this would be a "stop by" or whether she's asking if the cousin can join for dinner. She asked if she could come for dinner.
Now, I know this person is aware that this is a somewhat intimate event and I assume that she is aware I'm hosting (because of how I roll generally).
I haven't responded yet - how should I handle? At the end of the day, it's not going to break the bank given the already significant cost, but do people truly have no manners?