Yeah. If it's going to be a Robin Hood thing, charging money is sure to invite a visit to the Fulton County Jail. Free = cool. Charging money = criminal enterprise, where Georgia has liberal RICO statutes.
Good news, since apparently your time is less valuable than theirs you will have no problem undercutting them.
The economics are irrelevant. I'm pointing out that replacing shitty behavior with slightly less shitty behavior is still shitty. Do you have an issue with people posting their observations on a web forum?
Sounds like a market opportunity to acquire your own key and charge $49.99.