...I doubt he has the time to dink around with you...
You got a point there puppy-mud. When you get right down to it, police have BIGGER FISH to fry. I mean, seriously: They deal with robberies, rapists, murders, etc...
Reminds me of the time years ago that 7 or 8 of us were hunting an old town park demolition project (installing artificial turf , ripping out the old turf, etc...). And ... obviously ... we had to do it at night (can't detect during the day when the workers are working). This was in a blighted part of San Francisco.
One night we heard the sounds of gun-shots coming from somewhere @ the nearby street. A minute later, we heard the sounds of several sirens from multiple approaching cop cars. They were racing up and down the street, apparently looking for the shooter (we found out later there'd been a murder). But ... we paid it no mind, as we were hunkered down inside this dark fenced demolition site.
About a minute or two into this chaos erupting on the streets outside our demolition site, a cop came running through the fenced/closed park, with his gun drawn. He stopped at the first md'r and asked "did you see a man with a hooded pullover run through here ?". To which we answered "no, we didn't see anyone run through here". Then he paused, looked at us and said "what are you doing ?". We said "metal detecting". He just shook his head, took off running again, saying "I have bigger fish to fry", haha
However, park rangers might consider it an issue (if we're dealing with cultural heritage, blah blah). But cops on the other hand, seem like they have bigger problems to deal with.