My very large post didn't make it 🙁
Like every other production operation, when they run a batch, they will test X amount. Reliability tests, run time tests, output tests, etc.
You can't test every one to make sure it's perfect. If you get X amount of bad ones in a batch, or lot, you either check more, or if it's like where I work, you scratch the lot and blow up what you messed up. I doubt SF does that 😗
However, if you test 10 in a lot of 500 and X amount are good, there is a very good chance it's a good lot. The odds are small of the ones you are testing being the only good ones in a large lot.
What I do, we test almost a quarter of what we make, then we fire almost all of those to ensure they are exploding on contact. Have an idea of what I do yet lol.
The fact that SureFire ships their lights with batteries, points to a simple guess that someone on the production line hits the button to ensure the thing even works before stuffing it into a package. Now this depends on how automated SFs production line is and how many they run a day.
That information is from production lines in general.
I could be very wrong, I doubt anyone at the Coke facility is twisting the tops of the cokes to make sure they are on tight. I also highly doubt they are taste testing them hehe Well, I hope not.