I`m a little late on this subject, but...... Various Certification Agencies are teaching Solo Diving. Ultimately, each diver is realistically Solo, when it comes down to it. Irresponsible would have been if a diver was LEFT solo from a group. If a diver ELECTS to go solo, he/she is obviously comfortable enough with their skills, knowledge, ability and equipment to do so. I`m not necessarily advocating solo diving, but I do it myself and I don`t think I`m being irresponsible. I know my limits and I pay much more heightened awareness of my environment and equipment when doing so. If I feel I may be having the least little problem, and there are no other divers nearby, I`m goin` up. No questions asked. My regular buddy and I always have a dive plan and it usually involves the ultimate seperation factor. We both agree that if we lose one another, we`re on our own. BUT we do agree to surface, check for a bubble pattern, and continue he dive unless we feel here may be a problem.