I used the USA/US code for our trip to Phoenix the middle of March. I signed DH up for a wizard number and got an extra $25 taken off of our 9 day rental. When I made the ressie I got a great rate (I wasn't really happy, it's much more expensive to rent in Phoenix) Anyway, I called to check the ressie and there were 18 ressies instead of 1. I talked to CS and she said that all was fine, just bring the printout with me incase. When we got there, we had over 30 ressies and no rate code. I showed the person my printout and she put the price in and off we went. When we returned the car we didn't have any problems. The rate was correct and we got $25 off! It really seemed like it was going to be a big deal before we got there, but everything was fine since I had my printouts. We even let them fill the car since their gas price was 10 cents lower than the gas stations in the area.