On star and other such systems, can work just fine with out you even knowing its turned on. By saying it is mandatory and charging you then when you sign the paper work its then known that you know it is active. It all works similar to any service you pay for TV cable, phone or cell phone. Even electricity, they control it's on and off at the "office". So even if you don't pay for Onstar on your old 2003 Cadillac, that does not mean they still can't listen in, or tap into the OBD2 port and have full scan tool access.