Have you discussed this with the landowner/permission giver? A person needs to be on the up and up with the landowner. Mine knows everything that I have and do on his land. And he's even told me to let him know if anything is disturbed and HE will do something. He also has a couple other guys that have permission and we've sectioned off who hunts where and who stays out of where. Just 2 weeks ago the neighbor property owner asked him if anyone was on his land because he got a cam stolen. I got a call from my landowner asking me if I knew anything. So I know he's good on his word. As for missing pics, its a possibility someone is erasing some but it is also a possibility that the deer may get spooked out of the area for a day. I have days of missing pics in good areas all the time.