So, have you ever considered the phenomenon of phone usage in movies and tv shows? Notice how they rarely say “goodbye?”
If not, here’s a handy video reference for you:
Crazy rude when you think about it, right? But it’s a form of conservation of detail, i.e. we the audience don’t need to experience every little bit of the conversation as if it were happening in reality. We tend not to even really notice, and it saves a lot of time getting rid of all those “hellos” and “how are yous” and (most importantly) “goodbyes.” Conservation of conversation, if you want to make a nice tongue twister out of it.
My characters do not speak on walkie-talkies correctly. Oh, I made a stab at it way back when. Because radio communication of this kind isn’t full duplex–which is a fancy way of saying that when I’m holding down the button to talk to you, you can’t also be talking to me–the protocols are such that you want to be sure you say “over” to let the other person know you’re finished talking and ready for their response. When you’re completely done with the conversation, you’re “out.” “Over and out” is actually derided as an unnecessary redundancy. As you can see if you clicked the link to the old comic, I made an oops on that. My cover story is that Suzie was just putting on a show for the cameras, and also these folks by and large aren’t ex-military (that we know of, except, perhaps ironically, the rather undisciplined Uncle Chuck).
Shortly after that, I decided I’d take a page from the phone situation above and just let the realism slacken in favor of saving space, time, and flow of conversation. They talk on their radios the way we might talk on phones, with the occasional “copy” or “out” sprinkled in for flavoring.
Realistic? Heck no. But this is one of those situations in fiction where I think the trade-off between realism and efficiency is worth it. So whether you’ve noticed or not, there you have it: my radio waiver.