I don't think she'd cancel, and if she DID, oh gods, would I hear about it, from her AND Dad.

She did mention a hotel offhand during the conversation in question, so I will inform her of our decision and if she doesn't like it, I'll hear about it and bitch about her unreasonableness after the fact. I find it telling of me that I was super-excited and nervous about Dad having a good time when he visited, and I'm waiting for this visit with Mom to be OVER with before it's started.