My thing is, if we're going to the theater it's a treat so why not splurge on popcorn and a coke?
When I was a teenager, my friends and I would sneak in alcohol to the discount theater. Those were some of the best times. The theater was rarely crowded and we caused chaos or just made out in the back.
One time we drank a bit too much and after the movie we saw finished, we snuck into Scream. The people got so pissed because we sat in the back and gave away who the killer was. Yea, I was a punk, but damn it was fun.