I dont really ride skateparks often enough to be a model etiquette follower but if I cut somebody up I make sure I apologise straight away even if I am not 100% in the wrong. I find that loosing my temper with the scooter kids etc just puts me in a bad mood for my ride and when that happens I may as well load the car back up and go home.
That being said if a kid is being un courteous and then loud mouthed about a near miss or collision I tend to find a look or a "you need to be careful else you are going to cause s crash" seems to do the trick. If you show that you are wound up for some kids that then engages them in a gamevof wind that bloke up.
Thats my experiences anyway both indoor outdoor on my bmx but by no means are they the right answer.