One day, fully alert and sober at something like 5 PM with no excuses, during a thunderstorm, I heard tornado sirens go off. I thought to myself, "sheesh they are only supposed to run tests at noon once a month, and not during sto- oh"
But to the credit of Nest/Google/Alphabet they replaced it free of charge. It was just an off-the-cuff comment I made on Twitter and Nest said send it back. They sent a new one, a new model, and when it arrived I sent back the older model. The new model is much better essentially zero false positives due to water vapour.