I don't know. UL doesn't make their rules openly-available. You have to pay them to read them. But Nest's website says UL's rules forbid the silencing, and I s

I don't know. UL doesn't make their rules openly-available. You have to pay them to read them. But Nest's website says UL's rules forbid the silencing, and I see no reason to think Nest would lie about it.