The property we bought last year in SW MO. already had several "No Trespassing" signs on trees around the 2 sides that were bordered by Gravel or black top roads. I saw where several had been but only a piece of the sign was left and the nails, most likely hit by tree limbs. So I took a couple cans of purple paint and painted trees in areas that I thought a 4x4, SxS, or ATV might try to enter. I think most everyone around there is respectful and after purchase we discovered some of the "In-laws" own the property on one side and another bought the property south of us! So in a matter of speaking, we kept the property "in the family" and I think that will help keep people off it while we are away.
With all the signs posted I suspect at some time there was issues with trespassers, I imagine people not from the immediate area, I still carry a cordless hole puncher when we're on the property working or scouting it out. Plus there are bobcats, coyotes, possibly a rare bear or mountain lions in the area as well.