I like a well-designed safety on my gun, but like undead said, the shooter is ultimately responsible. as for knives, I hate em. I see no reason to put a safety on any knife for *most* applications. If the knife is well designed and well built, it should not open under normal carry conditions. Something like a gravity knife is a good example, as many of these are held shut by either a mechanical or spring mechanism that in no-way limits the time it takes to deploy them or prevents them from being intentionally deployed. The only time I can really understand wanting a mechanical "safety" switch, would be if I was jumping from a plane or riding a motor cycle. Even still, safety switches are never a 100% and you should always respect a knife for what it is, deployed or not. Just my 2c though. :)
