Well, about the guest book being filled by RMT spam - I imagine that could be a thing. It would require spam bots to actually move and walk into houses and such to do it though. It could be a crafted thing that you make or buy and then place by the door inside your house. So you could choose not to have one, messages could be deleted from it, and ultimately you can always set your house to private or just not have the guest book out in the house. I think there needs to be some reason to visit peoples houses... I like seeing peoples houses, but always feel like a creeper when they happen to be inside. It's like... Hello there, I'm just going to run around your house and silently judge the decisions you've made...