How do you know they do it on purpose? Do you speak Russian and hear them say “Let’s fuck in the pay only rooms?” Every one of those apartments have multiple cameras for catching action at different angles, and I’m willing to bet the tenants don’t even know which ones are free and which ones are not. And most of them will fuck in any and every room at the drop of a hat, or spend most of their time going naked or near-naked from room to room. This sounds like another complaint from a freeloader who doesn’t want to ante up.
I’m willing to bet they already don’t know.