Especially since they don't even have to be surface mounted. It'd really be nice to be able to trust devices.
Sure you can. Think out of the box. A small speaker that sticks over the microphone opening and constantly plays a recording with two voices overlaid, one reading the Gettysburg address and the other reading the declaration of independence, constitution and amendments. You would have to be shouting to be intelligible over top of that.
Even better, think of how a microphone works. Its just a magnet and wire, right?
Could you place a small magnet over the mic to essentially lock it in place? no movement == nothing to record.