If it is a legal issue, then call the legal athorities (cops) so they can do their job and enforce laws. There is a reason we pay cops. I never try to do their jobs. I have my own, and I'm not equipped or trained to do theirs.

If it is a moral issue... you're SOL. No way you can enforce morals on others. They will trash talk you for trying.

Frankly, I doubt much less than expensive tickets will change their behavior, and even then, probably not for long. I would guess that they are more concerned with their ave MPH than ANYthing else at that point. Not getting dropped being paramount. If you stop, you get dropped by those who don't.

If they got tickets, the ride leaders MIGHT start putting forth a larger effort to obey traffic laws.

I absolutely would not put my lively hood at risk trying to get ashholes to stop being asshholes. That's a loosing battle.