The urban trapper incident is human error and not the pocket clip...
Human error is exactly why the pocket clip might be a bad idea.
I generally don't use clips unless I'm specifically doing work where it needs to be accessed repeatedly. Otherwise, I can understand the problems here. I've never lost a knife, but I have had exposed pocket clips get hung up on stuff , and even have knives pulled out as a result. I have had non knife pocket clips scratch stuff up.
Like just about any solution, the pocket clip can have unintended downsides.