"Webcam tape" is a successful meme. Good for it!
But, prima facie, most people should be more concerned about their microphones - and this meme is rare. Obviously loads of software fixes (up to killing the device driver), but reversible hardware would be better.
How about: "insert a dummy plug into the mic jack to prevent sound from being picked up by the internal mic. create a dummy plug by cutting off the unneeded portion of an old microphone plug" (Still software-mediated though.)