Not even my old ADT/GE system had a second pin to “cancel.” But a duress pin would solve that too.
As I said above, and confirmed in the reply, if the base is smashed after the entry delay starts, at the end of the countdown plus 30 seconds, it will trigger a response when it doesn’t get an all-clear from the base. I’ve verified this on my own system when I first got it by triggering it and then pulling the power and battery, as if it were totally offline (ie smashed). It definitely triggered a response.
And as for the Alexa Guard situation, a) that’s Alexa, not Ring, so you’d have to address your concerns in a different forum. B) it isn’t a traditional glass break sensor. It just listens for loud noises, period. So if you are home, you’d set it off just with normal household noise, not to mention having all your conversations actually recorded, vs only potentially getting recorded if someone says something that sounds like the wake word. In guard mode, they’re already awake and listening constantly.
Alexa Guard is for listening in when you’re NOT home, but it’s not meant to replace proper security with sufficient sensors. If you’re concerned about smoke/CO while home or away, get Ring Smoke/CO Listeners for your existing alarms if they’re less than ten years old, or you’d need listeners and new alarms if older than 10 (or the First Alert Z-wave Combo Smoke/CO detectors that are certified to work with Ring work well too).