This list of reasons seems to be exhaustive when it actually comes down to refs. I don't think I've ever witnessed things being thrown onto the field/court except when the refs are simply bad. Maybe we need to find a way to better express our frustration toward the refs; only there isn't a lot you can do besides boo and throw things. I don't agree with throwing things at the refs, which I think is what is really being done typically, no one is upset at the field, teams, players, etc. we gave other ways to express our frustration to our team or other things, but not toward the refs. It's Like a drive by, they come in, make their calls then run off to never be heard from again. If someone comes in and steals your car you might be tempted to throw something at your car as it speeds away. So what's our alternative to express frustration about refs?
Maybe they should handout "throwing approved" items to be throw at the refs as they leave? I think rice and confetti should be fine since we shower newleyweds and heroes with these. Who could complain about that? Maybe biodegradable packing peanuts? It's a win-win, those who want to express their frustration get to do so and the refs feel like the grand marshals in a parade. (Gatorade? Coaches only get this treatment when they win really big games or to cap off a big season)