I second that
They pretty much have to release it as GPL if they've used any of the core linux library's.
DashPC - The Linux Car (since 1999).
Dash LCD, Via Epia, GPS, XM, OBDII, DSSC Shutdown Controller.
As seen in the book Geek My Ride
Umm, actually, no they don't. Have you ever actually *read* the GPL? How about the LGPL?
Your belief that they have to release it as GPL if they use the core libraries is an oft-stated reason for a company to NOT release their software on Linux.