Warbler said:
I don't know about your country's movie theaters, but here theaters take a dim view of people smuggling in their own food and drinks. They want you to buy everything at their snack bar. Its how they make a lot of their money.
*followed by dismissing suggestions of overcoats and nail varnish*
Smuggle it in a purse. That's how my mother got me contraband snacks for the theatre when I was a tot.