Ok, I might have been a bit harsh in saying "any". I did get a pretty positive impression from one sensei on the Karate episode that he would have done the show regardless of any spin.
Basically, it's just my opinion that you frequently have to agree to show people in a positive light to get a high degree of cooperation from them, or at least give them that impression. From observing the show, I got that same impression from some of the various teachers they've had on as well. To tar them all that way is unfair though, as some gave me a very positive impression of their attitude, in that they seemed to think their skills spoke for themselves.

