Yes, it is. I see parents at my nephews games sreaming and yelling at the umpires and getting so mad that they storm off. It is horrible. I mean I want my kid to win and be successful as much as the next...but I don't want to completely embarass them in the process.
I see this all the time at my 3 nephews' hockey games. It's very sad, makes them looks like idiots, can change the outcome of a game if the parents yell at the refs, etc. Some people just don't get it. It's about letting their kids ENJOY playing the sport, not WINNING every game.