Carvedog, I think you're very right in the "I own the slopes" mentality causing more chaos every year. However, music is definitely a variable that not all riders can handle well. While it may be possible for you and buddies to enjoy tunes while making turns, my guess is you're all conscious beings that are smart enough to make logical decisions and maybe check your surroundings. That cannot be said for everyone on the mountain. Just as there are idiots in your everyday dealings, those same nudniks want their turn on the snow with their cool new earbuds. Then you take away one of their senses that restrac2000
mentions, and you have the potential makings of a bull-in-china-shop scenario.
Other factors that I feel will always be in play with this kind of deal - Teenagers(self explanatory); park junkies who are usually of the teen variety but almost always dooshy; booze, hangovers, and I suppose maryjane; the previously mentioned early season masses quantities wanting to ride white ribbon of death; and basic lack of mountain knowledge/etiquette.
Also, I really think the argument of snowboarders being assholes is stupid. If you're an asshole, you're still an asshole whether you have 1 or 2 pieces of wood, plastic, and metal attached to your feet.