Decent points here. I know personally that I wouldn't want to waste a run spotting for someone else. DH, you're right, while its the "right thing" to do, it won't really ever happen. I usually watch someone go over a jump, and don't drop til i see them move away from it.
As for people in the parks that shouldn't be there. They're tourists, plain and simple. The first thing I think about when I pull into Blue is an amusement park. Thats what mountains around here are like. What do they care if they just do whatever they want? They're never going to see you again and they may only make it back on the snow once or twice.
If you haven't noticed the 2.44E99 posts, these people are the ones that put money in the mountain's pockets. From their perspective the more n00bs flocking to see parks they can't ride the better. Park passes are the way to go and I hope every mountain around here has 2 parks and a pass in a few years. Not much more left to say.