They use to pay the homeowners yearly to report people they saw in water with detectors, I don't know if they still do. I know this because the salvage teams came into Kellyco for equipment repair when I worked in the detector repair center. It is considered a crime to illegally detect in the water in lease areas.
Just the ticket and getting detector back or vehicle out of impound lot would be too much for me, there are over 750 miles of legal beaches to hunt to worry about 50 miles where it's illegal.