http://www.w2sjw.com/radio_sounds.html

But, I speculate key tones will only make things much more worse, as most of these girls playing Arma-3 don't know how to talk on radios.

An idea would be to add this as an option for the player to turn on, in an attempt to avoid talking over others who simply activate the mic and wait several seconds to talk... I do the same sometimes.

Also, key tones are useful for other uses too.