Riding on the big red truck with someone is different than sharing a regulator. Everyone has his or her own SCBA facepiece for a reason. Disease transmission is a concern. Appropriate PPE/BSI procedures go out the window when you start sharing regulators in an out of air emergency or any training exercises. Problems arise when there is percieved discrimination due to one's sexual orientation, history, number of partners, etc. There wouldn't be a problem working at the same station, but I can't order someone to do something when they have what they believe to be a legitimate concern about their personal safety. I know that there is a concern sharing a reg with anyone; if you wouldn't share a reg with someone, you shouldn't be diving with that person. Black water is no place for an issue with trust. Has this been an issue for anyone else?