As someone who worked in a DMV for many years issuing driver’s licenses — even though I wasn’t a license examiner — I think I’m the closest thing to your target respondent so far.

The craziest thing I ever witnessed with my own eyes was a dude who somehow managed to lose control at <15 mph, jumped the curb, and smashed into the guardrail. Needless to say, he was not issued a license.

The best story I ever heard from a co-worker happened immediately after she came inside swearing a blue streak because, during a part of the test where the examiner stands on the curb in order to observe maneuvers, her customer drove up over the curb and straight into her knee.