Sorry, but I will never understand why people not only think it would be ok to sit in more expensive seats that they did not pay for, but even get upset when the staff prohibits them from doing so.
That said, I do remember more than a couple of times last year during a wet and cold games, and very people left in the stadium, they not only let people sit anywhere they wanted, they even opened up the club house. So they can be flexible at times.