An.existing utility easement which was legally recorded but is not shown on the property plat is one example. The associated costs could range from nothing, to having to relocate driveways and/or buildings.
That is an excellent example. I had an ambiguously platted easment on a property, and it took years to straighten out that it was only for emergency access by the adjacent owners, and not for every Tom, Dick and Harry to traipse through my yard to the public park on beyond. (Guess whose HOA wouldn’t allow the side yard to be fenced?) Ultimately, it was solved by the engineering firm who drew the plat writing a letter clarifying what they should have made more clear, and my insurance agent explaining to the park ranger the park’s liability for funneling traffic through private property — and finally the park and the HOA allowed No Trespassing signs. People still try to trespass, but not as many; and the police community relations officer affirmed our right to tell people to leave because it’s posted No Trespassing.