Just a few comments...
Every provider I've seen in my short hobby life has told me of some guy wanting BBFS. There are horny guys out there that definitely want the skin on skin experience. I'm horny, but not THAT horny. One provider, early in my hobby days did provide BBFS for a fellow hobbyist and he was very freaked that he didnt resist.
I limit my risk by never going down on a provider. I figure what the heck for? I'm sure all if not all, 9 out of 10 aren't in to it and I figure I'd just be agitating her tender area for me or the next guy. I'm sure they get sore and the less unnecessary friction the better. I mean if you get something out of going down on the muffin, great. If you don't, why risk it?
It's supposed to be all about me anyways. Good, interesting thread.