The hypothetical person I described in https://news.ycombinator.com/item?id=28361769 could certainly imagine deciding to not provide information her family needed to know for that reason, or not to attempt to meet up with them, because she is in a distinctly different position from an aircraft! And real emergencies are full of people in situations like hers, and worse.
That specific message is ill-advised. A significant portion of that message could be transmitted safely and would be way better than "Nah, not going to key the mic at all unless it's encrypted..."
"Katie and Uncles Bob and Jim are all moving from X to Y. We're armed only with our AR-15s and have plenty of ammo. We had to leave behind a few other things at the house, but we're moving safely and expected at Y before dark."
If the family knows they don't own any AR-15s and don't have any uncles named Bob or Jim, the message is received (or enough of it to be practically useful without being an unneeded forfeiture of OpSec).
Probably I'd think Katie was off her skull, or someone who didn't know us was trying to trick me into going to Y. If I did think Katie was just lying, I'd wonder if she was lying about Y too.
