My wife picked up her first rental at Budget BUR airport 2 days ago, the guy worked there was a jerk. He refused to put delta skymiles number in there without seeing a physical card, so we went to Duty manager, who put number in there but told us only for 1 time.
We reserved a Compact car and got a Mercury, but I'd rather to have a compact car because I am too young to drive a Mercury! Receipt did not show anything when we returned the car.
Yesterday, I went to pick up my first rental at AVIS BUR airport, the service was great, booked a compact, got a convertible and the guy put my delta number in the reservation without asking for a PHYSICAL CARD.
I have not return my car yet, but from many people report, Avis receipt in your email should show" miles earned 10049". However, the receipt you get at car rental may not show anything or something like "miles earned:OVR"
Also, I think adding your wizard number will not affect the bonus as long as your price booked via delta.com doesn't change and rate code still shows "FL".
I changed all booking from Budget to Avis.