Reputation FAQ: Trespassing

House owners can add 'friends' to the friends list of the house. All characters on the account of the house owner will be auto-friended to the house, except characters that are owners of another house.

All players who are not on the friends list of a player building will highlight grey to the owner and his friends if they enter that building. This allows the owner and friends to deal with trespassers without fear of getting flagged.