It is very hard to prove that a bolt has been overtightened. If I were the manager at that garage, I would have fixed it for you quickly. Because it's easy, and has a good effect on PR
. But they obviously don't see it that way. So you know where not to go.
A dry torque is fine, as long as the wheels come off twice a year, and everything is OE or OEM. If you have some thing else, it can be a totally different matter. An example might be magnesium composite rims, stainless steel bolts, and iron holes. My favourite friend then would be Copaslip. It is THE very best you can use.
Imagine you are going to mount some wheels, where the bolts squeecked when you removed them. Maybe you had the "snap, crackle, pop" sound when they loosend. When you tighten those again without Copaslip, they might be weakened by the vibration under stress, and might even get further weakened by the vibrations under tightening. This might go the way the chicken kicks even with correct torque.
In any case, losing a wheel is a lot more damaging then losing a bolt. A flying bolt might cause some damage, but so will the 5 that leave your wheel before it falls off. Not to mention the rest. So if I don't have a torque meter, I would prefer to overtighten.
In Oslo, the bus companies are reluctant to tighten their wheels properly. The result is several wheel losses every year. I have found wheels as far as 700 meters away....! This goes for all of the companies.
The outer wheel in the picture, (Don't worry, it's a Benz. A Citaro) took a stroll on it's own on E18 in Oslo. When the driver finally relized something was wrong back there, he exited to the left. That manouver made the wheel leave the spindle(?) and it continued 40 meters. There it hit the side fence.
Whenever bolts squeeck, they need lubrication, or maybe better exchange. If you can find good ones. I always use Copaslip because it stops rust, and takes care of anode/katode. And it won't dry out.
Always clean the inside of the rims carefully, and make sure no rust or any other matter is left on the contact area on the spindle.