No Parents on the Field - Don't do it

Soccer is a physical game. Sometimes, the physical play is beyond what is acceptable for the game. In those situations, the referee is charged with calling fouls and issuing cards.
Do not step on the field as a coach or parent because the referee is not making a call you want. Do not step on the field as a coach or parent to yell at the referee. Do not step on the field as a coach or parent to yell at or disparage a player. Do not step on the field as a coach or parent to yell at a coach or parent on the field.
I can recall being at recess in elementary school and having occasion to be tripped or pushed down. I survived. All the excuses we make up to step onto the field are just that. Excuses to do something you know is not allowed. You know what is more traumatic than getting tripped or pushed down? Parents coming out and screaming and yelling about the contact. The kids want to play a game. Get off the field.