My dad and I were fishing at a reservoir down in southern Missouri about 40 years ago. We were going into a cove, but there was an old guy fishing there out of a jon boat already in the cove, so we continued on down the bank. Maybe 15 minutes later a speed boat full of young people take their boat into the cove and speed back out again. This happened once more. As the boat was making a third run the guy in the jon boat pulls out a shotgun and fires over their heads. Speed boat left and did not return.
If I'm fishing a new lake I always try to be nice to the locals. You never know how much firepower they have.