> Perhaps you can think of a way to design an alerting system which cannot be abused - but I can't.
Isn't the obvious answer decentralization? Have persons necessary to send that message in different places across the country/outside the country needing to sign it for it to be sent. All taking the responsibility of following protocol in these cases.
I’d go further, and predefine the available messages and bake them in - $place is {under attack|on fire|underwater|beset by the whooping palsy} etc. - and then the decentralised send no longer needs distribution of a message, just an ID and enumerated metadata, like location.
Then the men with guns come and you can earnestly say “well guys, i know you want to declare the eternal republic of Basingstoke, but all I can do is send a warning about a tornado in Slough, is that close enough?”
I think that is right and with the way Ukraine and Iran is going, we will need smaller decentralised data centres etc too. Its coming from a sad, bad place but it may be better and more democratic, less centralised.