AHR Uninvited Guests

Somewhere I had heard (I can't remember where) about uninvited guests showing up to people's traditional or AHR receptions. My Dad was shocked when I told him this and asked, "do people really do that? No way!" My FI also has a hard time believing this. Has anyone had this happen to them and, if so, how did you deal with it (especially if you had a reception where you had to give a guest count and meal selection choice)?

I think the problem that happens more often is you send an invite to a couple and they send back their RSVP with more than 2 marked.. ie they invite their kids or additional family members.

Some people are clueless about the process and/or the amount of money weddings cost per person.

My girlfriend had the opposite problem.. many people RSVP'd and then never showed!!! She had many empty tables and tons of food left over. Talk about mad!