They run in packs,
the answer is for ethical anglers to show in groups (which ethical anglers typically don't do) and force out the unethical anglers.
I've been on the water at times when I was the only one not setting the hook every cast...
I've reported snagging before, and the warden told me ' good luck trying to explain to a jury of peers that this guys intent was to snag a fish - all he has to do is say that he felt a bite and release any foul hooked fish and I cannot do anything...'

it sucks