This thread reminded me of a federal crime fighting agent who patrolled the US Army Corps of Engineer land around Lake Oahe in SD back in the 2000s. It’s against Federal law to collect artifacts of any kind on COE land, and he would use binoculars to observe people walking the shorelines (usually fishing) and issue citations carrying stiff fines if they picked up anything, even fishing lures. Almost no one caught was aware that they were doing anything wrong. It became such a problem that our US Senators (Tom Daschle being one) wrote a letter to the Corps. The agent was transferred. Crime skyrocketed.
When I was a kid in the 60s, I would walk the shoreline during camping/fishing trips looking for spent .50 Cal casings left over from when they had fighter pilot training grounds in the area during WWII. For a grade schooler, finding those was cooler than anything.
I did find arrowheads and pieces of pottery in a plowed field on a friend’s farm, though.