Or at least that's what the infamous THEY would have you believe. I poke around people's homes and shops and whatnot as I'm sure most people do, and I'm finding (this may have always been somewhat of a problem, I really have no idea) things that strike me as, mainly, greedy. High prices happen, yes, but wtf. I've named this one, "Please click my sign, new player, so that I may lulz!"
I've seen several others mixed in with groups of sales chests. Maybe so, though, in this situation, although no apartments or games were present.
Alot of times people put signs on their chests like this because they use it as a donation box. They normally have it marked however.