I once helped with beatiing the crap of a commercial techie with a laptop in a cofee place, hacking ppl's gsms just for info, poor bastard. He was trying to gather information for a few cooparations in my country. like habbits, brands ext.
I am not the paranoid type at all, but i want to be left alone or at least think i am alone lol, if i was i'd take some wierd encrypted SAT-phone and not N900

On-Topic, you are right about ppl not trying to pick calls on radio freq's however, for instance in my area due to sooo many radio channels i only have about 3-4 freq's i can use with the FM trans. imagine how many ppl use the exact same freqs Also. military use scanners all the time for their own use, they probably will get a laugh out of your conversations