Smart choice on at least using your own regs. Lord knows when the last time the shop's regs were serviced. As for the BCD, I would tell the owner straight up "well if you had decent gear in proper working order, we wouldn't have to use own gear just to complete the course we paid for safely". As for when he questions you about where you got your gear I would tell him something along the lines of "I would have bought my gear from you, however, part of my purchasing decision is based on customer service, which includes classes, and faulty gear with no fix is bad customer service".
You mentioned before of using a bp/w.....I am not a confrontational type of person, but I would have brought it and used it especially if it was what I was going to dive in. I normally tell my students that if they are going to purchase gear, go ahead and use it. I would rather them learn in what they are intending on using so I could show them how to use it properly in class rather then have them try to figure it out themselves after. Its safer that way. The only time I would object to them using their gear is if it was not functioning properly or clearly needed service to dive safely
You mentioned before of using a bp/w.....I am not a confrontational type of person, but I would have brought it and used it especially if it was what I was going to dive in. I normally tell my students that if they are going to purchase gear, go ahead and use it. I would rather them learn in what they are intending on using so I could show them how to use it properly in class rather then have them try to figure it out themselves after. Its safer that way. The only time I would object to them using their gear is if it was not functioning properly or clearly needed service to dive safely