I dunno George. Part of that checkover would be to get the car on a lift so you could at least see the rotors from the back side. While it’s up there, since you’re diagnosing thumping, you’re probably gonna do the wiggle test on the wheel to check for play, because if it’s that you’ve just invested all of 10 seconds of your time into making a sale.
And if you’re doing the wiggle test and your face is right up at the wheel and you fail to notice that a lug nut is missing?