I just went online and ordered tickets to see “Dawn of the Planet of the Apes”. 
I printed the confirmation, and was curious about one of the notes seen at the bottom:
OK, I understand the motivation for the first sentence. If a person was being totally obnoxious in the theater, management would want to get that person out of there.
But I don’t quite get that last sentence. Under what scenarios would management want to designate where a person would sit?
The place is nearly full and they make people move one seat over or something so a couple can sit together.
If you’re sitting next to one of the empty spots for a wheelchair, and a disabled person wants to sit there with a friend. The manager may make you move to accommodate them.
I was going to say both of those things but I was beaten to the punch :o
EDIT: I’ll say that I’ve seen both situations happen in real life, so it’s not just a guess.
The theatres where I live have started using assigned seating for the premium showings (you are able to choose from the available seats when you book your tickets).
If your theatre has showings with assigned seating (or is planning to add them), management may have simply updated the terms and conditions on all of the tickets rather than going through the process of figuring out which tickets need the additional condition and updating the website logic.
Indeed, a couple of our newer theaters have tickets that are purchased with assigned seating. Of course, the seats also are extra wide, recline, and there’s a bar in the lobby. It’s pretty sweet really.
I have to say that I also really like the new “assigned seating,” because it eliminates the rush to the theater in order to snag good seats.
The only problem is, I went on a triple-date a few weeks ago and we were supposed to see How To Train Your Dragon 2. The date bought the tickets through Fandango. Before going to dinner, we picked up our tickets from the kiosk without giving them a glance. After eating, we walked to the theater and saw we had tickets for Transformers 4. Checking the receipt from Fandango, we had tickets for HTTYD2, but since the seats were assigned, we felt like we were stuck to see all the Baysplosions, because someone else might be in our seats at our intended movie (or it might be sold out).
On another note, if you only ever have a day to live, go see Transformers 4, because that movie feels like it goes on forever.