Obviously if the dealer screws up, you're covered. But do you have any idea how hard it is to crossthread a drain plug? I've been changing the oil in my cars since I was about 16, and have yet to accomplish this. You've got to be pretty mechanically inept to cross thread a large bolt like an oil drain plug... in which case, you probably shouldn't be changing your oil in the first place.

 

i bet the mazda dude didnt hand thread it in first, easy to detect a cross thread doing it by hand, wht a moron

 

You didn't say who cross-threaded the drain plug on that Mazda. Was it a DIYer, or was it a Jiffy Lube type place?

If something bad happens at the dealer, you may never know about it. If there are six bolts holding a part on, and one of them gets cross threaded and stripped, what do you think the chance is that they'll do an expensive and time consuming repair to fix the problem, and what is the chance that they'll just use five of the six bolts, smile as they replace those plastic covers, and figure nobody will be the wiser?