The rotor was screwed to the wheel hub with a single large Phillips screw. It had stripped instantly when he tried to remove it. After fighting with it for over an hour, with drill and dremel and hammering the screwdriver into the soft screw to try to get it to bite, he finally got it out. The auto parts store informed him that they didn't have any in stock--because they weren't needed.
It turns out that the screw is a assembly-line-only part, holding the rotor in place while the car moves from one station to another. Once the rest of the parts are on, it isn't needed. If you are repairing the car in one place it isn't needed at all.
So: not an essential part. OK. No point in greasing the thing before you put it in--why waste a step on the assembly line? And no point in getting a real screw, just use one of the soft metal screws like those that you get with cheap curtain hardware. At 6 per car, say 100,000 cars--the factory might be able to save as much as $10,000!
Of course it costs you or me an additional 4 hours or so per car... I don't know how the pros deal with them, but they're probably exasperated too.