There are quite a few people out there with more money than common sense. Many of these people buy boats. Most know little or nothing about what the rules are, of those that take a required course, many will retain that knowledge just long enough to take the test and then forget it in midst of trying to decide whether one ice chest or two will be required to hold their beer. (Nothing against beer, quite the contrary)
Which is why I gave up flying dive flag long ago, unless perhaps from boat. They seem to attract these idiots rather than keep them away. There are times and places places I will also wait till at or very near surfacing before popping an smb, for the same reasons.
Our local lakes have more than fair share of these idiots. Often driving fast, powerful boats. You get a lot of "lets haul butt over there to see what that is" people. I usually come up anchor line at boat or shore if in any way possible.