Have you considered the possibility that your (so-called) friend is sneaking onto the site on his own to metal detect when he knows you will not be there? Many years ago, a friend of mine in Key West invited another friend of his to metal detect a beach in the Keys where a Spanish Silver Piece of Eight had been found by accident. My friend (Roy) knew that a Spanish Galleon had wrecked not far off the beach and the Silver bars and some other items were salvaged but very few coins had been found during the salvage operation. Well, they went the first time and found several coins that had fell out of the sand dunes and had been covered up on the beach. They went back again and began digging into and metal detecting the sand dunes and found (I believe) 15 coins this time andI believe one more time and found more coins. (Note: I wanted to note that digging into and metal detecting the sand dunes in the Keys back then, was not a big problem as long as you returned the sand dunes as they were before you dug and avoid the Sea Oats or allowed them to recover.) Well, one day, this so-called friend showed up where my friend (Roy) sold Sea Shells and was showing off his' coins. Roy having a photographic memory, asked this so-called friend where he had gotten several of the coins, to which he stated on the last couple of metal detecting trips to the beach. Roy knew that this was not the case, so one night, he drove by this so-called friend's apartment and noticed that he was gone. Roy then drove to the site (the beach) and found him digging and metal detecting the sand dunes using a head mounted light and that he had totally destroyed much of the sand dunes and Sea Oats. This ended the partnership and this so-called friends damage to the sand dunes and Sea Oats, ended ever being able to dig and metal detect the sand dunes forever. Roy attempted to go back but found that the Monroe County Sheriff's Office had put it off-limits and a Deputy was stationed there in an attempt to catch the culprit that had damaged the dunes and Sea Oats. You might want to falsely indicate to your (so-called) friend that you can't metal detect certain days (of which you know that he possibly can) and sneak by the site to see if he is there metal detecting. If he is, then I am sure you know what to do!
Frank
Frank you are absolutely right...
I have personally had this happen to myself once as well...
I had a local "hotspot" that was a location I found...
Was an old location on the Clearwater Beach where in the 70's stood a popular bar that had long since been gone...
I invited a guy that showed some interest... I gave him a detector to use... and we went to several beach spots and found very little to nothing...
I kept the "honey hole" a secret... but after hearing him ***** moan and complain about how the hobby sucked and so forth for hours...
I decided to take him with my girl and I to the honey hole...
We found a moderate amount of things that were silver and gold...
I saw it in his eyes... the greed...
After that I called him a day or 2 later and asked if he wanted to go back with me to the hole... he declined and said he a had bought a detector off a buddy and that is buddy was a detectorist...
and his buddy may want to go with us... I told em ehhhh well I would rather not include more people...
ANYWAY... that weekend... went to honey hole spot... stated swinging ... nothing... then I noticed barely visible divots...
I had reserved a certain area off to the side that I said to him I had already worked... THIS WAS UNTOUCHED.
So I called him later that day just to see what was up and to trip him up...
After beating around the bush he stated he and his buddy had went to "test" out his new detector...
When I asked "where" he went... he was like " not to any of your spots"...
This guy ended up telling many people I later found out about this spot... to make himself look "cool" or whatever...
Spot is so clean now you could eat off the sand.
I have heard of this same type of scenario happening to others many times as well.