SeaBreeze..great pictures. I think the dogs totally love what they are doing, or it would be very difficult to train them. If a dog really doesn't want to do something, or is afraid to do it the chances of coercing them into it on a dependable basis are small. These dogs all look like they're veterans of this sport and are willing participants.
I have tried this with various of my schnauzers when we used to go to Galveston frequently...While all took to the water as they were taught to swim in our pool, only one ever took to the surfboard. All the others would jump as soon as they got the chance. Shotz would hang in there pretty well, and of course it wasn't anything like the training these dogs go through, but he really did like it and would willingly jump on the board and stay with it as long as he could.