Your take on this case is the correct one. As soon as they saw a path or landscaping or any evidence of usage, they should have first called the survey crew to put up the little orange flags, and then the fence contractors to surround the place. Period. End of story. Sad but true, but it is their fault for being neighborly.
There is a fairly good chance that with enough press and publicity they can get their land back. Then of course they will need to promptly sell it, because it is unlikely they would want to live next door to these greedy bastards.
The mind boggles when you think of how the Kirlins could get even with the greedy bastards by selling the property to a ""particular type of buyer""...hehehe.
Revenge is sweet and payback's a beotch!