Dollar/Thrify have introduced an ‘Express Fuel’ option in a move copying Avis, and recently, Hertz.
On rentals driven 75 miles or less, a $13.99 fee will be added regardless of fuel level, unless a refueling receipt is proactively produced at time of return. The terms specify the refueling location should be within 10 miles of point of return. See the Dollar announcement and mirroring Thrifty announcement.
This is designed to eliminate short rentals returned where the fuel gauge still says full. In practice, lots of people who refuel do not know or forget to give their receipt and get dinged. After hours returns may require challenging the bill later which lots of people won’t bother.
I generally avoid Dollar/Thrifty, especially in states with toll roads, because they charge a per day unlimited toll use based on point of pickup, charged every day of rental, regardless of usage as long as one toll is tripped during the rental. As an example, Newark is $18.49/day. Ouch!