I won't name the girl, because I don't want any trouble for her, but I've gotten BBFS at Lucy's.
This particular session was proceeding as normal, but I just couldn't seem to pop. Realizing the issue, the girl suggested that I remove the cover and continue. I was hesitant, but with the lack of blood flow to the big head, I followed her advice. She admonished me to not blow inside, and, of course, I complied with her wishes.
That is the only time it happened, and I had chosen not to advertise it out of respect for the provider who I felt had gone the "extra mile" to make sure I left satisfied. I didn't want her to get any unwelcome pressure from mongers, nor any flak from the MMS.