I don't think it's so secret anymore.
Last May, DH and I wanted to sneak back and check it out. It was empty when we got there, but not for long. Before we knew it, about 15 people had gathered out there for a pilates class. Then a big bunch of kids came back and were clowning around, so we decided it would be less congested on deck 9 & left.
P.S. They lock the access door to that deck at about 11:00 pm at night as there was some "hanky panky" going on!!!
Sign now says it's closed from 7pm to 7am ...