I was raised that there were things adults did and things that kids did. And when you were an adult you could do what you wanted but that stupidity wasn't going to win you points. But then, my parents never drank at home--not even beer. It was never seen as entertainment or a necessity. Parents who joke about getting drunk or drink at home are part of the problem.
if you honestly think you can get kids to not drink before they are 21 then I dont know what to say to you. Kids are going to drink. Teach them to drink responsibly and you dont have problems.