I agree that there are many experienced shadetree mechanics out there that can handle refrigerant service. However, there are many more of both the DIY and professional mechanics out there that should be kept far away from anything that has such a great potential for harm in the wrong hands. Have you heard of Freeze-12? Horrible, dangerous stuff, and used by way too many people trying to cut corners. This is one aspect of the auto repair industry that should be tightly regulated, to protect the service technician/mechanic, the public, and our environment. I have nothing but the deepest respect for the damage that improperly handled refrigerants can cause, and I have breathed a small amount of phosgene gas, courtesy of an accidental release of R-12 against a hot exhaust manifold, which burned the R-12 and released the gas. Not pretty, and I am a certified professional that is careful in his work. I have seen the results, and heard the horror stories, associated with the improper use of tools and products in HVAC service. I am not against making a buck, I just want there to be some accountability.