The principle idea here, prevent foraged items (and personally, anything that spawns) from appearing on claimed land, I like. Reduce the overall effectiveness of large areas of land by claiming them. However, given the current mechanics of the game, that seems like, as others put it, only a method of further discouraging play, due to either the grief/harassment of players who are depriving the region's locals of resources, or simply preventing people from benefiting from controlling a large area.
However, if the game system gets to a point where we can terraform all terrain types into other types, that would seem like a more reasonable way to reach the solution you want. If swamps could be drained, mountains gradually plowed over, rivers filled in, and mudflats grown in, then we could effectively turn huge regions into completely paved empty terrain that lacks any useful features, given time and effort on our parts (or bots parts, whichever).