Ok, but "prom" is not a proper noun! Would you say "I'm going to airport?" or "What are you wearing to restaurant?" Although you WOULD say "I'm going to Miami International" or "What are you wearing to Bookbinders?"
I go through a similar argument with my friends in Pittsburgh who insist on asking "Can you ride me home?" rather than "Can you GIVE me a ride home?" I try to explain that what they are asking is if I would get on their back and they will take me home, but its always useless.
