People kept saying "overbooked", but from what I've read it did not seem like an overbooking issue. More like UA realized too late that they need to fly 4 crew members to operate a flight next day.

Then for people who says "he paid for the ticket", well the people who were going to fly the next day also paid for the ticket, are you going to deny them their tickets because 4 people wouldn't?

It's a question of denying 4 pax or a full plane worth, I would also choose the 4.

Although ORD-SDF is like only 5 hours away by road, I'm surprised no one takes the $800 and drive. The doctor could've just leave and drive.

(I'm also well aware that UA could also transport the crew by car, that's another option)