I would be more than happy to let my friends in-game into my house to use them. The bonuses are to good not to share. If I could place them outside without worrying about them being stolen, I would!
So say you have like 11 houses in Buckward vale on one block, which is very possible, each neighbor could simply focus on one icon, and you would pretty much save a lot of time and money which isn't a good idea? I like free stuff, but yeah.