Originally Posted by
Often1
To put this in perspective, during a random quarter (2018-Q1), AA reported 363 IDB on 34.2 Million passenger boardings. Worry more about being struck by lightening enroute the airport than being IDB on a US carrier.
As far as an individual situation goes - someone driving to the airport on a sunny morning, booked on a flight that is oversold has a much higher chance of being denied boarding than being struck by lightning