Not being an electronic wizard, I will just have to defer to those who make the rules and say, Yes its a possibility it will interefer with navigation.......
However in the real world on non airliners folks use them all the time and survive.
One thing I feel caused the problems was the phone companies themselves. Cell phones were designed for line of sight. So when you turn on a cell at an unusual altitude it hits more than one site, thus creating confusion within the phone system....Who knows it may even cost them more money.....Wouldnt that be a shame.
Maybe someone like Rhodie could jump in and explain. He worked with this stuff for a while......