Seriously. I called the hotel today to get an updated reservation list. Someone assumed they were invited and booked a fucking hotel room. Invitations haven't gone out yet but everyone we're inviting received a save the date which included our website which had all the hotel info. This person must have heard from another guest about booking the hotel, and went ahead and decided that they should book too.
I told my mom (this person is her friend, but not a really close friend who we were inviting), and she went "oh my, guess we have to invite her." My mom is financially taking care of her friends on the guest list so it's not a budget problem, we have extra space at the venue, and I know asking this uninvited person to cancel their hotel reservation would most likely be a friendship-ending move on my mom's part. The whole thing is just so awkward and weird. People are strange.