My in-laws house faces a river. The lots are straight but the river takes a curve. The next door neighbor couldn’t understand that when he looked out his window toward the river, he was overlooking my in-laws land. My FIL caught him one day actually moving the property line markers. He finally paid for a survey and had the markers replaced. Then, just because he wanted to, he parked his old rusty boat trailer down in the far corner of his lot. When my FIL died, I scrapped the old trailer. I didn’t want the jerk neighbor hassling my widowed MIL.
It has been my observation that people can be turds about this kind of thing...and we wonder why so much violence was committed over land disputes throughout history!