The person I responded to said his was coming loose. That has been my experience with that type of link. I don't have one of yours. Maybe it is special and doesn't come undone. Still the person who has one says it does come loose. I suggested he use a wrench to tighten it. You suggested it doesn't come loose but use pliers if it does.
I'm not saying his quick links didn't come loose. Nor am I saying that quick links are some infallible object that can't possibly fail. What I *am* saying, is that finger tightened quick links simply won't come loose unless something acts on the gate to loosen it. That could be other gear in your camera bag as objects shift around while you carry it. That could be another piece of gear on your body. (If this was an aircraft or vehicle application, we would talk about high frequency vibrations, but that isn't so relevant in a camera strap).
If I came off as trying to deflect the original poster's issue as simply having not happened, I apologize. My intent was to say that there is some force going on in his setup that is rubbing against the gate and opening it.
I'm not really sure why you would suggest using pliers instead of a wrench or insinuate that the link does not come loose as the owner stated. PR I guess, but it didn't convince me.
I only suggest pliers as a solution for folks who are concerned about the gate opening and/or are working in environments where there is a greater chance something could be rubbing against the link. Why pliers? They are a universal tool that everyone has access to, often right in their pocket. As for the finish, these aren't big industrial safety links; it doesn't take much torque with pliers to instill a bit more confidence than finger tightening.
As for your exhaustive studies let me ask what version you're on now with your strap? Seems like I recall exhaustive studies finding the optimal solution before a time or two.
Optimal solution takes price into consideration. When we evaluated quick links against the other common solutions (gate clips and side release buckles being the most prevalent), we found that the size, simplicity, reliability and strength of the quick link was the best and the possibility for failure was the lowest. Side release buckles are very bulky in the 1" size required for sufficient strength and gate clips are very easy to make fail with minimal twisting action.
Take price out of the equation, and there are better solutions. In fact, I've been quite vocal in telling folks about Swiss Le Hooks, but their availability is highly limited and getting a pair in the US will cost you $55. They are quite amazing though.