It's not DIR, it should be pretty much every diving agency. It may be part of DIR, but other systems that certainly are NOT DIR use it. It's common sense. Personally I have no problems with DIR, but it seems some people that dive it believe that they are then only able to dive with other DIR divers. I've read stuff on DIR sites saying "only dive with other DIR divers", and it's that stuff I don't like. I'll dive with anyone I know to be a competent diver who is familiar with their kit and mine. I'll only refuse to dive with someone I can't trust, which sadly involves a number of instructors in my club.
Safe diving,
Matt
Safe diving,
Matt