Originally Posted by WarChild

The reason why I ask is because here where I live (British Columbia, Canada) you actually have to bring the car back to have the lug nuts re torqued after I think 50km. It says so specifically in the purchase agreement. Failure to do so results in them washing their hands of any problems that happen after.

What I would do is go in with a level head, be polite and firmly ask them to make this right. What I wouldn't do is make comments about what "could have happened". I think this will set the wrong tone right off the bat. In reality you're not going to be able to "punish" the mechanic, who most probably didn't do it on purpose, and the best you can hope for is to have everything fixed up with as little fuss as possible.

Anyways that's a pretty shitty situation and I hope they clear it up for you.