I don't know if this is unusual or not, but there is an individual that I occasionally dive with, who (to the best of my knowledge), experiments with diving techniques beyond his training. The best that I know this diver, certification- wise, is of about the same level that I am (rescue diver), with perhaps a few more dives than I have (about 100). I am in no way saying that self training isn't possible in some areas, but it just doesn't seem very wise in my opinion. I know he's been experimenting with solo & decompression diving with no formal training & has recently been trying to pass himself off as a technical diver. To their credit most of the technical divers around here have been smart & asked to see his credentials & refuse to do any technical diving with him, when he can't produce them. He's basically trying to get by with a don't ask, don't tell philosophy. He is ambitious with his diving, but doesn't seem to want to go through the proper channels to get there. When I dive with him I watch him very closely for signs that he's going to do something I would consider unsafe. I do not go beyond my training. If he starts to go into a situation I'm not equipped to handle or a profile beyond recreational limits, I will thumb the dive and head for the surface. If he follows or not is his choice. He doesn't stray from the plan every time, but does occasionally. I believe firmly in the buddy system, but it is a 2 way street. I have dove with technical divers many times & I am not shy about letting them know where my limits are, & they respect it. I have nothing against technical diving, in fact I may get into technical diving someday, but right now I know I have to get many techniques perfected first & I'm in no hurry. I see some of the things this buddy is attempting to do & do not see a good outcome form it. Unfortunately talking to him does no good. He seems hell bent on doing what he's doing. I feel by receiving proper training you are prepared for situations that you may not even think about when you self train. Is this common occurrence or just a buddy that I'd be best just to not dive with?