Most hubs are DC powered anyways, the netgear one i've got here is 12volts so that shouldn't be a problem...

Except that the voltage in the car can vary from say 9 to 15+ volts between cranking the starter and high revs with an enthusiastic charge controller... And the 12V line usually has plenty of hum and transients... Might or might not affect a given hub, but it's often more to it than just "it's 12V".

/Michael