I have this exact scenario on the ground that I own. I bought the ground in the fall of 2008 and it has been a battle with neighbors ever since. On any given fall I can count 6 to 10 tree stands at 10 yards or less from the property lines, most facing into my property. The "fence sitters" as I call them drive me nuts.

My "solution" was first to post my entire property lines. I now use the orange plastic signs that slide over a T post. I have them located such that if you stand anywhere on the property perimeter you cannot not see at least one of these signs ... and generally you will see 2 or more. Every sign has my cell phone number on it as well. I check them every spring before crops go in and every fall right before gun season opens as that is when the fence sitter issue happens around my property.

What I do for every stand that I find sitting around 10 yards or less from my property line is I make a sign of some sort. I've used 2x2 posts with plywood attached (about 24"x24"), I've used old election type of signs, etc. I then use sharpie or print something out in bold stating that this is private property and that I basically have a zero tolerance policy when it comes to trespassing or shooting deer off of my ground. I put on there that if you need to track a deer onto my ground to call my cell phone number (listed on the sign) and we can arrange for that. I put these signs on my side of the property line (very close to the line) and face it right at their stand. They cannot hunt that stand and not see the sign.

For me this has worked pretty well. One neighbor called me up the first year after seeing the sign, we had a nice conversation, he actually moved his stand about 10 yards deeper and turned the way it faced, and hunts it still to this day. He has called me one time to track a deer on my land. I had another neighbor who he and I agree to disagree on the topic of shooting a deer across the property line and to date he has not done so that I know of, but it is possible that he has and I have not caught him. I have another neighbor that our conversations have gotten very ugly and he has flat told me that he will shoot whatever and walk where ever he wants to and every year he seems to re-position a couple stands right on the property line ... needless to say I will have him arrested the first time that I catch him. I have yet another neighbor who is super nice and he will stop by and talk hunting, tip me off to what he is seeing, and always leaves with a "I'll call you if I need to track something".