[quote=@whizzball1]
<Snipped quote by The World>

Speaking of that, like I asked, how do we know if people in different locations can hear each other? Do we have to specifically state "everybody can hear this"? Or do we just reply and hope we're right?
[/quote]

Private versus public communications. Easily inferred, and the devices are smart enough to know what is/isn't, as long as the people behind them are as well. A general rule is that if they're someplace everybody can access like the base, it's public, which is also an explanation of how people know when to show up. If it's someplace nobody can get to, it's most likely private. It's also extremely low-key. It won't really be mentioned unless necessary because it works independently.