Be properly evil
Now, the properly evil asshole would first weaken the jack close to the handle so when finding an offending TV, you insert the jack and push it sideways till it breaks leaving the tip inside rendering the TV eternally mute or till somebody in tech support goes through the whole manual and finally gets to visually inspect the input from inside the apparatus.
PS: The technique applies to any device with minijack input. Use this knowledge wisely for it is the wisdom of the assholes.
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Oh, how devious!!!!!
Somewhat related: Yesterday the wheelchair pushers planted the wife and I in front of an oversize TV screen in the Charlotte airport (CLT) while awaiting our connecting flight. (Think the old CNN captive viewing days.) We were forced to watch 35 minutes of nonstop DISNEY commercials on an endless loop. Now I really understand why airports are gun-free zones.
And with how many places practically give away cheap, corded headphones and earbuds, it could cost you next-to-nothing to keep a handful of these around!