Here is some wisdom from Scott Babb, creator of the Libre Knife Fighting System (the primary knife system we train in at Guard Well). This video talks about using a Kershaw pocket knife offensively. The way he deploys the knife requires that you take off the clip as it comes from the factory, and put it on the other side of the knife so that you can carry and deploy from the front pocket. Kershaw conveniently makes a trainer companion knife.
While a fixed blade guarantees the knife will deploy correctly every time, there are legal considerations to carrying a fixed blade. And sometimes laws on knives are more complicated that gun laws. A folding knife requires practice to ensure it deploys. Scott explains how to grip the knife in the unfortunate event it does not deploy properly and how to use your target's body to fix it.