Did this ever happen? As far as I know there are only 6 permits for the Chinchorro Reef and they are only given to locals. I dive with Chencho of Trintones del Mar based out of Majahual. He has 2 of the 6 licenses. He is the only one I know who will organize overnight trips.
The most knowledgeable person around, he knows that reef by night and is very meticulous in the maintenance of his vessel.
It is definitely worth the trip.