Once at my Hertz HLE. It was 2 years ago, at 5:45 PM right before they close. I booked a compact for the same price as economy with an upgrade coupon to intermediate. The manager planned to give me a Ford Fusion, but the previous renter smoked in it so he had to take it out of service. He looked at the coupon and said, "It says as available." He gave me a compact Cobalt instead.