Hello,
There's no proof of if that printer is his or not, so that could have easily been dealt with by asking for it to checked on who's it is by the administrator helping you in the sit. As for the Kos Sign on the Building sign, that is fine to do, it's not against the rules. Even if they're building, they can kill you if you enter their side of the base. The prop block looks like it was dealt with as well.