I understand your dilemma. After building my biggest pond (about 18 acres), stocking it, everything else, I once found remnants of a seine along the shore. I was mad and frustrated. I thought about it some more and realized they wouldn't have caught much or done much damage as it has few good spots for seining (mostly too deep).

Since then, we've caught two people getting ready to fish. My brother spotted them pulling in lane to go to lake. He and a sister followed up and called me. I got there in time to take pictures, contacted game warden and states attorney, and etc. They each had to pay fines of about $200. Haven't seen them (or anyone unauthorized) back since. We do have some trail cameras up to help identify anyone that might. There are some pretty decent trail cameras now that can send photos via cell so you get real time notification and have solar chargers so you seldom have to visit. Might be worth checking out.

Also, as I get older, actually catching the fish and etc. is less important to me. It is more about myself / family / friends relaxing. I wouldn't be opposed to some others fishing it as long as they followed the rules and helped out in some way in exchange. Maybe those kids would help maintain it in exchange for access rights following your rules. At one point, I had a surplus of channel cats there that would have been easily caught and weighed around 15 pounds each. I didn't have much time to dress them and would have allowed someone else to catch them if they would have given some catfish fillets to one of my brothers (who was badly injured in a fire). Didn't really know of anyone I could really trust to do that and not also catch / remove the big bass / HSB / Bluegill. I think those big catfish have since died.