My FI and I are coming onto the end of our RSVPs, and last night one of my friends from high school messaged me saying "I will definitely be coming with a guest! SO excited" which would be great if we had invited her with a guest. We clearly marked the invitation with just her name on it, but I guess she didn't understand. I'm not sure how to go about this, everything was budgeted out for a certain amount of people and I don't know even know who she's planning on taking. Should I just leave it be or politely mention something to her?