Is AUTHOR wrong in the post ? POST : There's a local bar/club where I live that has free cover for people over 21 before a certain time (10 or 11). This is obviously because people over 21 are probably going to be buying alcohol. 

Is it rude to go to the club, take advantage of free entry, and then not buy any drinks while I'm there? Obviously it isn't rude to not drink alcohol, but should I at least buy some water or soda and tip a few dollars? I've gone before without buying anything and I felt like an asshole.