That's a pretty broad generalization. "Those damn crazy racers!!" Well, there is a common courtesy thing that maybe one doesn't try to mosey through the race course unless absolutely necessary. Especially on a buoy race. I know the sailors I race with obey the RRS and ColRegs when on the course. We have had a few power boats think its a grand thing to mosey through us. Most people though know we are going to be out there because we have been doing it for over 50 years. We get spectators in power & sail on the edge of the courses. Its not hard to figure out where the "lines" are. And no, we do not take up the whole lake as that would be not a good neighbor thing to do.
The truth hurts.
I was a commercial seaman for 20 years. Ships navigator. Yes, I well know racers expectation is for every one else to do the courteous thing and go around their race. Even if it forces 700 foot ships into the rocks.
The courteous thing to do would not set up race courses in busy harbours, channels, ferry routes and commercial shipping lanes. But no, its every one else who is supposed to be courteous.
I don't know how many times I have had to alter ships courses in designated channels while some red faced beered up racer screams "can't you see I am racing here.".