You let law enforcement deal with those breaking the laws. I'm dismayed at some of the solutions some of you are mentioning and hope it's only internet talk and you really wouldn't do such things. Let's see, sailboaters think they should own the waters, no power boats..trawler owners now think they should own the waters, no other type boats.
Then you get upset when anchoring or disposal of waste laws are passed based on what a few of your brethren do. I don't complain about the anchorages near my house, nor the PWC's. I do complain about dangerous or illegal conduct, but I see very little of it by the PWC's near me. I know the rental companies issue stern warnings and law enforcement is quite active in our area.
When I read about firing cannons and tossing poly rope into the water, I should be shocked. I find those and other retaliatory suggestions disgusting. If you observe illegal activity, then report it to the correct people. In this day and time, you all have video capability on your phones, capture it.