What caused the problem was that the installer disconnected the Pass. Airbag light (housed in the center faceplate) and then turned the key on when testing the radio.
The code that is set is the Indicator Light code, resettable by the dealership. We reset that code a lot after radios are installed. The installers are getting better about it, but there's a learning curve.
Just have the dealer reset the light. We charge 0.5hrs, if that's all the customer wants, no diag, just turn the light off after the radio was installed.