Correctly torqued wheels can and do come off, not necessarily due to the torque itself more often it’s down to poor fitting, such as not cleaning mating surfaces, incorrectly tightening the bolts (ie to the right torque but in the wrong sequence) I’d hazard a guess in the op’s case the garage (or whoever fitted the wheel) most likely used an impact wrench and didn’t bother to torque the nuts afterwards, you see this frequently at tyre outfits unfortunately.
Every time I pick my truck up from Scania after it’s had an inspection or service where the wheel(s) have been removed, I find a tag attached to the steering wheel warning me to get the torque checked within 25 miles, more than once it’s needed considerable tightening even though the tag tells me the level the wheel was torqued to.
As for the OP getting anywhere with the garage, good luck I’d suspect, ultimately, as a driver it’s down to you to make sure the car is roadworthy , after 90 miles(presumably of more than one journey) I don’t think you’ll have a leg to stand on.
If any of that applies then thats down to the garage, not the customer. A line on the invoice asking the customer to check does not absolve them from negligence, and garages have been taken to court and lost over this happening.
Correctly torqued wheel nuts are only correctly torqued at the time of fitting.
Studs (and bolts) can stretch under tension, so a wheel nut that was tight can become no longer tight.
I don't need to state any "scientific sources" for that, it's how materials behave.
In ~200k road miles and carrying out most servicing myself that would require wheels to be removed, I have never had a wheel nut I've torqued myself loosen off. I've not had one loosen off from a tyre change either myself.
I wasn't asking *you* to provide sources, I was asking the guy who claimed it was proven "legally and scientifically". If it was "legally" proven then garages wouldn't be losing in court when their customers wheel falls off after being serviced by them.