Yikes. The level of intolerance among you park rats is weak. Forget about the kids stopping well after the landing to wait for their friends (gee, NOBODY else ever does that!), at least they aren't sitting on their asses right in front of the chairlift or blocking the entire run waiting for the balls to actually go over a jump. By spotting their team mates, they are being safe, and can warn riders uphill if there is a digger. I can't tell you how many times I have barely dodged the remains of some incapable rider splattered all over the landing of a kicker because no-one was there to wave me off.
Those kids are encouraged to try everything on the mountain so they develop into well-rounded skiers; they are limited to 2 runs in the terrain parks all day, so stop your whining. By the time they are 10, they will be kicking your ass all over the hill.