As has been pointed out, there are lock back
designs available; however, the non lock back design is not inherently
unsafe.
Ever since the invention of the folding knife
hundreds of years ago, users have had to learn either to purchase a locking
variety or to never cut in a backwards direction. Many of us learned that
lesson as small children. I still have the scar to prove it. About
half the knives I have owned in the last 55 years have been non locking, and I
only have the one scar.
Ed
Ed & Wendy Hauser 2994 Mittower
Road Victor, MT 59875