its quite a bit of effort to come up with such coded language ahead of time and get everyone to remember it in a high stress situation without it also being decipherable, IMO. But I agree it has its uses.

but if you’re forgoing security anyhow, you could do the same with meshtastic and instead of a person on a roof it could just be a node on the roof, or in a tree, or routed via existing mesh infrastructure (many cities have quite a few nodes already). And that would have significantly more security than a walkie, even if its still vastly insufficient. especially with standalone lora mesh devices, which often dont have persistent storage of messages, or with some firmware modifications to make them more secure, it could be halfway decent.

I have mixed feelings about the practicality of either option really but I think radios stick out more in a crowd, and so does a person on a roof