Get an aeon minimote and create an automation in smart lighting that will turn off your siren when one of the minimote buttons is pushed. That should be eligible for local execution so if this happens again, at least you have a way to turn the siren off.
Of course you wouldn’t be able to disarm smart home monitor, so alarms would keep getting retriggered.
There’s no simple one size fits all answer, but there are things you can do to plan for the outages. And I think you should assume that there will be a major outage a couple of times a year and minor outages at least once a month, just because there always have been.
See the following thread for some ideas on how to approach this (this is a clickable link)
Anyone have their Harmony connect go haywire at the same time? My local remote stopped working properly (could not select activities through remote) coincidental with the Smart Things outage. Did not work all evening (but the app interface did). works ok this AM.
Hmm, now that you mention it, that might be the behavior I’ve seen in the past too. Although it’s been a while since this has come up for me (SHM armed and unable to disarm) so honestly I don’t remember.
That’s like reason # 1,001 why SHM is a really poor excuse for a security system.
Certain device handlers are eligible for local execution. The standard minimote handler is one of them. If you have a z-wave siren that works with a generic device handler, that can probably run locally too. Smartlighting is one of the only smartapps that can execute local automations.
That all means that if your hub’s internet connection is down, or the ST cloud is otherwise unavailable, an automation like the one I described above can still run, and it would be possible to turn off your siren.
However, the ST mobile app does not function unless your hub is connected to the internet and the ST cloud is functioning normally. That means it is impossible to arm or disarm smart home monitor.