Yeah, but a restaurant is specifically for food, so it makes sense that they would kick you out for bringing your own, but a movie theater is not a restaurant, like an airport or plane. I pay for the seat in the theater, and I'm not interested in their food.

They may have a policy against bringing your own food, but I don't think it's a reasonable policy and I don't see any reason to obey it if you don't want to and they don't enforce it.

If you want to make more money from the movie goers, just charge an extra buck for the ticket.