I've luckily never seen that myself!
Not being clear with kids is the biggest problem I see most often.
Most parents nowadays seem to think it's mean to think that it's mean or cruel to "show your kids who's boss", even though it doesn't have at all. Kids are still young, still learning and developing, and don't really understand what's going on in this humble little life, so if you don't come clear with them, and if you're not a hard parent in one way or another, then you'll end up with a kid that has learned that crying and screaming is the most effective way to get things done...
And, you know what's cruel? If that very kid grows up and reaches the tough life that's not being a kid whilst still thinking that crying and screaming is the best way to get things done...