[quote=@NekoJordan]
<Snipped quote by VKAllen>

A wat to stop with this is like tear gas or flash bomb for sight and high pitch whistle(like a dog whistle) for hearing.
[/quote]

This wouldn't be a problem if everyone doesn't suffer the same consequences when they are used. A dog whistle is producing frequencies that no human can hear. No matter how good your hearing is, you simply won't be able to hear it.