I have to disagree with this. Just because an operator is forced to use a tool that is not ideal for the situation does not mean that he or his unit has somehow failed. These guys frequently find themselves in tough situations that they might not have been able to plan or prepare for, and being able to use what they have, however inadequate it might be, to get the job done is one of the many things that separates them from everyone else.
Obviously you can find yourself in less than ideal situations. My point is that if you are going blade-to-blade with an opponent and you are using a folding knife, you have somehow lost the use of your rifle, your sidearm, your fixed blade, and you have no buddies to help you.
Could it happen? Yeah. We do train to be able to continue to operate in austere and unexpected conditions. However, putting a feature on the spine of your folding knife to stop a blade from sliding into your hand isn't going to solve the problems you have at that point.