Jordan....the same kind of issue with me when I was there at ITW.
I saw ITW during its last 3 weeks...the show was not sold out, of course, but it was pretty full. A full two rows were pretty much 85% empty in the back. I decided during a pause in the performance to sit down (as the ushers said this would be okay, since it wasn't sold out and we didn't distract anybody)...well...IN THE MIDDLE OF THE WOLF EATING LITTLE RED SCENE they come marching over to me and ask me "IS THIS YOUR SEAT?!" I said, of course, no, but I was SRO and I'd been told I could sit down if seats were empty...they pulled me out, had a latecomer sit there, and then moved me elsewhere...
Now, I understand that it was that person's seat, but they should have handled the situation between scenes, instead of distracting everybody. So I can see how there could have been a problem.
How to properly use its/it's:
Its is the possessive. It's is the contraction for it is...