I don't know - I see it this way: if the tech breaks anything while driving it, I'M certainly not going to pay.
My local tech (name withheld) will let you ride along and his method includes full-throttle accelerations, neck-warping turns and repeated hard braking. I figure the car is built to take it and if there's going to be a failure (or potential one), he's more apt to notice it at 6000rpm, wailing through some tight esses, not at 2500 cruising the boulevard.
Let me say, though, that my first such ride (in the old 300SDT) was mind-blowing. I was waiting for pistons to fly through the hood, wheels to fall off and the tranny to drop out a la the old AAmco commercials...