It's a oft-used gag, isn't it? Someone is hooked up with one of those microphones, and either gets caught saying something private that gets broadcast or is speaking eloquently with no one hearing them.
But, in my never ending quest to be make sure we are always aware of the power of our words and to remember that words can create, maybe the thought of a wireless mic might be a good filter. The next time you mutter something ugly under your breath, or sidle up to a friend at a public event and murmur something unkind about a third person, or add your two cents into a conversation that is unnecessary or snarky - imagine those words being broadcast over a loud speaker. Imagine them printed beside your picture in the paper, or in the church bulletin, or sent to your mother. (eek)
If the thought makes you uncomfortable - do the right thing. Either say nothing, or be the one who changes the direction of the conversation. Create a world of good with your words. Send justice and kindness and tolerance with your speech. That's worth broadcasting every time.