One word... VERY
It's not cheap equipment, it would be much cheaper to have a guy on hand with a really big knife. Just cut their tongues out, lets see them shout when they're now completely mute. Though knowing these people they would just text, so you would hear, BEEP BEEP, Brrrrrrrrrrrrrrrrrrrrrrrvt.
EHEHEHEHEHREOHASODJHSMSANBSD<MASDASLJHHKJASKHD CJ!
(That's the sound of laughter from somebody who has had their tongue cut out)
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