Pig, in the case of mines and town centers, players can't claim their land because it makes it impossible for their allies to access.
Further, many players don't have the Yeomanry skill, leaving them open to that attack regardless.
But more importantly, there's the matter of courtesy; no matter if the game allows you to follow someone all day and swear at them, for instance, it's not right to do so.
I also strongly disagree with the idea that "if it's possible it should be OK". There will always be a modicum of player choice, and one should be responsible for their actions in the game.
Also, Pig, this is a discussion on game design and ways to make the game enjoyable for all players. Terms like "lol" won't get you very far.