OK, what is it that you are doing then?
Well these systems have been in use for a while in aviation, they were designed for use in aircraft and as far as I know do not interfere with any of the other systems. The fact that I decide to use it on a plane that is just a bit bigger shouldn't make a difference. A lot of GA types have 99% of the equipment in a modern airliner anyway and they don't seem to have a problem.
So: you will do what the CC tell you to do and never argue ... unless you decide not to do what they tell you and to argue because you think that there is no reason to obey them?
PAXboy this is the place to have the arguement...not the cabin of course and I say again
I would never argue...as it happens I've never felt the urge to take a GPS with me on a flight and probably never would...but I can understand why some PPLs/spotters or whatever might.
Permitted in-flight but not during taxi, take-off, initial climb, approach and landing: Various devices listed, beginning with "Laptops with CD ROM or DVD drive" and including "GPS handheld receivers".
Some airlines think they are safe anyway...
Whether or not folks pilot their GA machine with two GPS units strapped to their goggles - I care not!! When aboard a commercial transport, you follow the rules of the company that you are paying to get you to the destination. That is the same if it is a taxi, a ship or an aircraft.
That is of course the bottom line...follow the rules.