Ive got a story that applies,
Back in High school 2 of my buddies and I were drunk and bored one night so we decided to go to an 18+ strip club (I was 18 at the time). Upon entering we were confronted by one of the employees telling us to buy a drink as it was their policy that all patrons must buy one drink. Being under 21 we had one option, water, which was 5 dollars for a bottle. Being the drunk high school assholes we were we pushed back at the notion of spending $5 on water and asked to speak to a manager. The manager came out and told us that we would have to spend the $5 or leave. At this point my genius friend using his best come back ability mentioned that we could go down to the gas station and buy water for less than a dollar. The manager then proceeded to tell us,
"OH YEAH!?? WELL THERE AINT NO TITTIES AT THE GAS STATION!!" and kicked us out.
Moral of the story is "there aint no movie" wherever you bought your water from so either be more sly bringing it in or pay 5 dollars for a water and refill it at the water fountain.