Earlier quoted context omitted.
False. There’s no such thing as “squatters rights” or anything or a statute of limitations. At any point the neighbor can sue you to protect his land. Further, when either property is sold, a survey will show the discrepency.
Depends where you live. You and GP are quite possibly speaking true of your respective locations but overlooking the rest of the world. In some jurisdictions, you are correct: the state owns all land, and purchase agreements are subject to consent of the state. No bill of sale, no rights. I know that the province of BC in Canada is one such jurisdiction. Irony here being that much of indigenous land in nominal BC is…
The various lawyers involved all said the same thing - if you don't put a stop to encroachments, you lose the property.
In one case that I knew about, the property owner moved the surveying monument 10 feet to increase the size of his lot. He built his house. 20 years later this was discovered, but oops, it was his land now. In another case, the neighbor did indeed build a garage on a friend of mine's land. My friend called the police, who told him it was a civil matter, not a police matter. So one day, he rented a bulldozer and demolished it. The neighbor called the police, but my friend showed the police the garage was on my friend's land, and that was the end of that. He figured the dozer was cheaper than a lawyer :-) and he was legally in the clear as long as he did it before adverse possession was claimed.
You might be surprised how often people lie and cheat about where the property lines are. It's worthwhile to have an official survey done for property you're considering buying - it can save you a lot of grief later.