They have never asked for ID or anything else when returning the car. They will just ask if you want to keep the charges on the same credit card and will then print a receipt.

However, you should be an authorized driver on the vehicle to make it legal to drive for that extra day incase you get pulled over, get into an accident, etc.

AFAIK, *most* corporate CDP's allow one person to rent a car and any of the coworkers/colleagues working for the same company to drive at any time without prior authorization.