Unless the station had its antenna on a balcony hidden in a potted plant, they had to run cables for RF and/or audio and utilities up to the roof. That means access to the service facilities of the building as well as roof access for a "transmitter shack" as well as a mast and antenna plus guy wires.
There is no way a pirate with the obvious significant ERP of this one could be hidden from the building super, and, thus, the owner or manager.
If the transmitter was on the roof, then it probably had to have its own utility hook-up and in that case, a new account with a new meter and wiring had to be installed. Not knowing the codes in that part of Jersey, I'd also wonder if a permit would be required.
All the more reason why the building management had to know something was there.