Outside of authorized "publicity days" and publicly advertised gang-bang scenarios, this is very unlikely. Random spectators in the eyeline of the average male performer is anathema to sustaining wood, which would result in longer production days and increased capital expenditures to cover fluffers and catering.
Now, the million-dollar idea would be to charge a contest entry or admission fee to select spectators, and relegate these patrons to a closed "HDTV Observation Room" fed live via wireless transmitter from all camera positions during the actual photography of a given scene.