The back of the houses on my side of our street border a farm field. We and our neighbors put up fences in 1997. Never had any correspondence with the farmer. We just received letters from the lawyer of the estate of the farmer, who died and whose property went to his sons, that our fences are about 3 feet on their property and they want them moved. Odds are they want to sell the land for a housing development.
Given that the lowest estimate to move the fence is $2000 per house, and that no claim was made in 18 years, we are going to consult an attorney about the NYS law of adverse possession. If you build on someone's property (which was not intentional in this case, we gave our property maps to the fence company when built), and they do not make a claim within 10 years, the law says you become the owner of the property. We still have the original receipt showing when the fence was built.