Someone in the FBI must have been absolutely ecstatic when they realized that with systems like OnStar it was theoretically possible to turn the microphone on and listen in on what was happening in any car using the system. Suddenly they wouldn't even need to bug cars - as the owners had bugged their own cars for the FBI! Except... no. A judge has ruled that the FBI cannot secretly eavesdrop on in-car conversations by getting telematics companies to turn their systems on. However, the ruling wasn't based on the issue of privacy - but on the fact that in doing so, the FBI disabled the OnStar system. In other words, if OnStar redesigned their system so that FBI eavesdropping could work at the same time as the regular OnStar system, they'd be free to go ahead. Update: Kevin Poulsen (thanks!) points out that it's not OnStar in this case, but rather the TeleAid system from ATX, which is used in Mercedes vehicles.