Warning: The following post may upset some!
You know, I got curious about that too. So I put my BM710 in the freezer and let it stay there overnight at about -20 Celsius (-4 Fahrenheit). No problem in the morning, frosty knife but opened and functioned smoothly. Cleanup and light oil after it was room temperature again.
Next step, get more radical. I got the lock and pivot area wet under the faucet and put the knife back in the freezer, now at -25 C /-13 F. Sure enough, after a few hours it was frozen shut, as one might expect. Blade or lock didn't move at all. Knife goes into my front pocket and after a couple of minutes it was thawed enough to operate smoothly. No problem again.
So there you have it. This wasn't in the least bit scientific but it was interesting to try out. Josh, you wanna give the ball bearing lock a go?