Trail Etiquette

This is me, bitching. I have seen a lot of crashes, near crashes, and bad vibrations lately when faster riders come up on slower riders and try to pass without saying anything to let the slower riders know they are about to be passed. This is rude, unsafe, stupid, and messes with my tranquility. There seems to be some sort of macho thing about blowing past people without saying anthing. It should be really simple. Say: "Rider back." Say: "On your left." Say: "Hey, moron, I am about to blow past you, get the f--- out of the way." Say anything, but say something. The next time I am out on the trail with a bunch of newbies and you try to blow past me in a tight spot without saying anything, I am going to see if I can get handful of the back of your jersey, so that we can determine just how far your bike keeps going after you are no longer on it.