Dr. Lecter
Contributor
Today the dive shop owner approached me said he saw I had a "stage bottle" an that I don't have the training for it that it's a tech level requirement and they go through hours and hours of how to use it. I said it's a pony bottle and he told me there's no such thing, people just use that phrase as an excuse and that having one causes more problems than it's worth. He doesn't want me wearing them on any training dives with his shop. He said "you don't see anyone else in my shop wearing one?!"
Personally, I'd explain that it's my dive, not his; that you have all the certifications necessary for the equipment and his opinion is relevant only in so far as it inclines you to spend your money elsewhere; that the course is, in part, about the importance of redundant gas options for deeper diving--of which the pony bottle is one; and, finally, that you'll be using it during the class dives until and unless the instructor him/herself forbids it and points out the agency standard(s) that give them the authority to do so.
If they put their foot down, do two things. First, get the name and agency of the instructor who made the call and report them to their agency. Second, demand a full refund for the course and, if you don't get it, give them the finger and have your bank handle a charge-back. Don't waste time trying to reason with holes: stomp on their throats (metaphorically speaking, of course) and drive on.