Ask The Salty Waitress: What are the rules of sneaking food into a movie?

Dear Salty: My adult daughter and I go to a couple movies together every month. It’s one of our rare bonding activities and I really look forward to it. But wow, theater food is expensive! I’ve taken to bringing in our own snacks in my bag, which seems to work fine. But for longer movies or ones that start around meal times, I’m wondering how far I can go with the brought-in food. Are pre-wrapped sandwiches and cookies too much? I don’t want to upset people around us or get us kicked out by the theater staff.