Just like maintenance. It is not free. BMW has a great way of marketing their "free stuff." Its either already included in the package/equipment required for Satellite radio and pricing could be adjusted accordingly.
If price is not adjusted, BMW could easily take away a perk they would normally have offered to adjust for this. Or move a perk to another "package."
Audi A5 - Daytona Gray
BMW 328i - Estoril Blue II