Audi USA chat has been excellent in response. Dealer promised to get radio code for only $70 this morning. Ouch. Thanks for the excellent detail in responses here. Looks like VAG COM full scan prints serial number of car and radio. Audi is sending radio code to email address after providing VIN and radio serial number + personal info to verify ownership.

 

My A6 is from Quebec (2003) and it had the radio code printed on a sticker under the spare wheel.