I have two Gen 3 vises and neither has a problem holding knives securely. Neither needs any form of tape or chamois to fscilitate a solid mount.
I agree with TCMeyer. My two Gen 3 clamps both hold very securely with strong tight clamping force an they both requires a fair amount of lever force to lock the cams. I choose to use the natural chamois to pad and protect the knife from scratches caused through metal to metal contact between the metal clamp jaws and the smooth knife steel. The chamois is not required to allow the knife to clamp securely. I use it just because I want to.
