I'm curious - don't certain agencies (such as police, armed services etc.) and other parties such as theater / corporate users, use encryption anyway? So the effect is just the same - you can't hear it...
Like I said, principle over practical.
Yes, they can and do, although most police channels are still not encrypted and listening to police and other emergency traffic is a common hobby.
The point is that if you where able to break the encryption you wouldn't be breaking any laws. Not a very good point mind you but its still there in principle
As I understand it its not so much to allow us to spy on our government as to allow us receive broadcasts from subversive or minority sources as well as international broadcasts to keep us from ever ending up in a China or North Korean situation where all news is controlled by the government.
It would be pointless any government to 'ban' the reception of any radio frequencies as all radio receiver devices can and do receive them - even if they cant use them directly. Also part of the FCC requirements for electronic equipment i believe...
Tell that to China.