I've never personally had an incident, but it annoys me when people bring little kids with them and then start telling people around them to watch their language. It's a public event. I know they say things on the loud speaker about no "excessive profanity" or whatever, but damn it if the 1st amendment is just wall art in the National Archives.
It's actually against the law to curse in public, and besides that, the parents are right, the stadium is intended to be a family friendly environment.