If that happened to you, I would find an attendant, they maybe able to pull a car out of the return area. Or have them check on the other side (there are 2 National locations at MCO, A and B).
I arrived today about 5:00pm. Lots of cars on the EA - Alero, Gallant, Corrolla, Stratus. Nothing exciting. I had a full size res with EA (pre-change) so I took a Camry from the full size aisle. There were quite a few cars on the full size, I'd say 15 or 20.