Have used the carlson code 4 times in a row at Newark airport, no problem. Tried to use it on the day before Thanksgiving and got a hard time. The agent wanted to see some travel agent identification card, I had no idea what she was talking about. I rent every week at that location and said I have never had to show any card and that the travel agent also said I didn't have to produce anything. In the end I got the rental at the carlson rate, but was told by the manager I would have to produce the card next time I rented.