We did the Behind the Scene on the Equinox in August. They must have oversold the tour as there were probably 30 of us (which was too many by half at least). And in my experience on other lines, it does usually sell out. It takes a LONG time to get that many people assembled, and the transitions from place to place seemed to take forever. In all fairness, they do have a LOT of ground to cover. That being said, it was very interesting. I would suggest you do it once (on any ship, it has to pretty similar), and it would have to be a big sale or done with OBC IMHO. No gifts, but it was fun to go to the bridge!