At my current workplace, they have a pretty simple dress code. You can wear jeans and a button-up shirt if you're a guy. You can wear just about anything except halter tops and flip-flops if you're a lady.
So what do several of the ladies do? They wear flip-flops and halter tops. As a result, management is going to crack down and issue a much tougher dress code. It would have never changed had everyone stayed within the rules. Now, it's going to be dress code armaggedeon and the same people breaking the rules are now going to complain about the new rules. Mindless, I tell you.