That one’s a tricky point.

Only claim land intended for use. Do not build close to spawn.
Claimed land must have a purpose (building something).
Claiming land can’t be used as a tool or weapon against someone else. Do not claim land to siege a player.
No buildings or shops can be set up near spawn in any world. Try to move away from eyesight of spawn before claiming/building.

So, if I come up next to a town, and claim a spot, build some cannons, and shoot you, it can be removed for violating rule 5. If, however, I build a house in your town, and we get along peacefully, it can’t be removed. If you suddenly change your mind, and don’t want me there, you can’t make me move. The only way to have that claim removed would be if I used it to attack you, regularly.

If you dislike each other, yet are relatively peaceful, then the claim can’t be removed. They’ll have to start attacking you regularly, or go inactive for months, for it to be removed.

Hope that helps?