One of the perks of carrying a traditional slip-joint is that people are comfortable around them.
There was an account by Steven Dick in his magazine about a guy who cut himself with a non-locking blade when it slipped. He was out doing forest service work, and got lost trying to get back to his work partner. He survived, but had lost blood and was not in good condition. Dick said that after the incident, the guy's wife bought him a locking folder.
I don't think I would have a slip joint for that reason. Of course, a fixed blade is even safer than a locking folder.
So in the upside down universe of sheeple, a knife's acceptability is inversely related to its safety. And this is nowhere more true than among educators and governmental leaders, who serve as our shepards.