See, now we're asking 2 different questions. If we're asking "what percentage of a dive shop's customers travel with their shop?", I would completely buy the 10% number. If we ask "what percentage of a destinations customers book group travel with their shop?", I'd bet my numbers are closer.
Dive shows used to be fun. I alluded to the rebreatherworld party and the Tech Party earlier. Yes, BTS had a tech party (which used to be sponsored by TDI, which meant that they bought the first beer, sandwiches, and the hotel venue) right next to the show venue. Walking distance. Get real drunk and stumble to my hotel room. Now, it's in a hotel that I have to take a shuttle to. That requires logistics, and I do logistics for a living, not for a party. The RBW party was at Cheesburger in Paradise. It was informal, and Curt brought a bunch of t-shirts, but it was BYOB and hamburgers. There was always a fight and whoever wasn't there got gossiped about. Seaspace had the Casino night. Seaspace had try-diving in the hotel pool.
One thing I noticed on Saturday morning is that I didn't see anyone younger than 40 before noon except for the Boy Scouts.