Here's a perfect example. I've just driven for an hour to do a Porsche Boxster, but sadly Mr Porsche isn't getting done today - despite the fact I took two screens with me, just in case. The result of the questions asked, the info provided was; has rain sensor, no top tint, no aerial, no GPS.
In actual fact, the screen he has; no rain sensor, does have top tint, does have aerial, no GPS. So I guess 1 out of 4 isn't bad - must be my or my company's fault it's wrong...