But you don't hear a problem in those technologies the way you do in AM radio. They just appear not to be working.

Your key-fob isn't opening a door. What's wrong? Dead battery? Door components not working?

AM radio: "I hear obvious noise in the broadcast no matter which way I turn the dial, and so does everyone else in their radio when they are in this vicinity."

one could also use a radio's aerial to find the direction of the interference, so by walking around one could hone in as the magnitude of the interference increased, pretty useful as anyone could find the source no matter what their expertise.