My local cinema is an Everyman they practically serve up a meal if you so wish, personally I don't go to the cinema to have my face in a trough, watching a film isn't synonymous with grazing, either or, go out for a meal or watch a film! I agree Nachos and the like have too strong an odour to inflict on other people around you.
My grandchildren are coming to stay over the Easter holiday sometime, so if there's an opportunity to take them to the cinema I will, as before with them and my own kids I've taken our own goody bags, I think I was asked once, years ago at an Odeon whether we had any of our own sweets, because they weren't allowed, damn cheek! better not go through my bag, I'd regard it as an invasion of my privacy 