Idiot drivers that pull out in front of you don't reserve this trick for cyclists. I also drive a motorhome (read BUS). Cars persist in pulling out in front of me. And I am clearly visible and large and dangerous. That apparently doesn't give them a twinge. I am afraid to hit the air horn (BIG and LOUD: sounds like a Semi), because then they will stop dead in the way and I will hit them.

You can't win.