I carried a Buck Alpha Hunter folder on a trip around South America. Used it for months as my main knife, most of the time in jungles and mountain environments, I didn't abuse it but I did use it hard (I has a multitool and a fixed blade in my pack, just in case). Anyway, when I was about to head back home I realised that I could close the blade just by pushing on the spine with my hand when the lock was fully engaged. I don't know when it began to fail, maybe it came that way from the factory. At first I was pissed off, and I still won't buy another Buck linerlock, but this is an example that if you're safe with your knives lock are pretty much irrelevant.
I like strong locks, but I don't know if there are any real tests that can be performed by the user without damaging the knife. I just stick to manufacturers I trust.