My original analogy is breaking down pretty fast here. I was trying to make the point that a purely defensive stance has to work 100% of the time, while an offensive weapon can serve both purposes to an extent. If I had known it was going to go this direction, I would have used the example of a Kevlar vest.

To answer your question though, 100% maybe. If my option was a butter knife. No. If we're talking about it decent 12 in knife or claymore or similar. Yes I would. If the flight is that dire, you can take a hard hit with a shield a couple of times, perhaps even a bone breaking one to an arm, and keep moving at a reduced capacity. As long as you can reach around one time and put the blade between their ribs while they're swinging a heavy shield, the fight is over. The point I'm trying to make, is that defense has to work 100% of the time, while offense only has to work once to do their respective jobs.