I've only had 1 knife go on me so far, and during use. I had a Gerber Gator and was whitling with it on a survival exersize with cadets. The pivot gave out on the 4th day of owning one. I only had it for about 30sec after it gave. Retry close/open, and then chucked into the wood. The officer's son had a Gator this last spring, 2yrs after I hucked mine, so it could be the same knife. I just didn't feel it was worth hauling back to my bag.
As far as I can remember from my dealer video(haven't watched in about 2 months), spyderco puts the blade in a vice just past the pivot, and puts force in the closing direction on the lock. The delica/endura in the vid just snaps a bit.
<img src="spyder.gif" width=15 height=15 align=middle border=0> also offers a breaking service. If you desire, they will break your lock for a fee and give you the results.
It helps new makers or makers trying a new lock. The info is only for your personal consumtion, not to be used for public, but its there.
Sal posted this service over in the Bladesmith's section of BFC... and a price I beleive.
My Word, My Honour, is my Life.