Instead of every cup or every straw doing this, some random and unknown percentage would do it. Combined with advertising, it could be an effective deterrent i

Instead of every cup or every straw doing this, some random and unknown percentage would do it. Combined with advertising, it could be an effective deterrent in a place where this is a real problem. People keep mentioning a bar's reputation, but at the end of the day if this is a real problem for your bar, your reputation is already screwed. This seems to me like a very pro-active way of working on fixing an already broken reputation.