My PM2 is my favorite knife, I don't trust linerlocks as I've had a junk one that would shut for any reason, and a kershaw skyline that would shut if dropped into wood point first, and almost took my finger off when stuck into a tree if not for the choil.
I'm with you that having a tougher lock doesn't make it better than the PM2, but its interesting, personally I don't think I'll use my PM2 to hammer nails so I'm not worried.
That's kind of the debate. In my experience the lock is tested in stabbing an object, and accidentally whacking the edge in tight spaces, as that's impossible to test reliably, that's why the worst case tests interesting in my mind. However obviously the real question is, in actual use does the stress on the lock even get CLOSE to the force applied here? There's a certain point where a heavier lock just adds expense and potential difficulty in operation with zero reasonable safety improvement.