That's a big problem in England too. They recommend you don't leave anything associated with GPS in view, whether it be charger cables or mounts. With my mod I can remove the mount and all thats visible is the charger connector. I can just put my sunglasses over the top of them. Having said that it's not really a problem here anyway plus if they want something it's usually unlocked...nice mod. I had mine up on the dash but i got broken into and it stolen. I also got broken into again even though the GPS was not in the car and they stole the charger and windscreen holder.
Sometimes it makes you wonder whether is worth having one...Tell you what, in UK you even have to wipe the screen where the suction cup has been or the filthy rodents see that and know you have a SatNav and break in to see where you are hiding it.
Same with GPS speed detectors etc.
Oh for a scum free world........