From what I have seen on my 2013 VW the antenna on the roof is for the satellite/gps/phone (up to 3 wires in it, mine only has 1) the antennas for the FM/AM are

From what I have seen on my 2013 VW the antenna on the roof is for the satellite/gps/phone (up to 3 wires in it, mine only has 1) the antennas for the FM/AM are incorporated into the windows...based on the brief stuff I read on the internet. So removing the roof antenna might do it...but then again it may render the system unable to start entirely (in the future it likely will). I suspect this is going to need to be reviewed on a car by car basis. And all of this assumes there isn't another antenna hidden somewhere else in the vast wiring loom (or on a pcb).