You should take your car back to the nearest GM dealer and ask that they remove the on-star system. It's an invasion of privacy.
Nah, I doubt I am of any interest to the FEDS or anyone else. But if I decide to become a terrorist or a fugitive from justice... I'll be sure to cut the antenna. "On Star" is completely useless without an antenna. That is why I purchased "LoJack" to protect my car from theft. It's only activated when it's reported stolen. And it can only be activated by the owner of the car with a password and serial number.
I still have faith in those of us who are willing to do more than snivel about how our rights are being infringed upon by Big Brother. As long as we stand up to those in government who want to invade our privacy and violate constitution rights, This nation will remain a Free Republic.