"False" isn't really binary. In my condo building we used to have in-unit smoke detectors wired directly into the building alarm, which meant whenever anyone in any of 200 units burned their toast sirens were blaring. The smoke was real, it just wasn't a threat to the whole building. This would happen once a month or so, and because it's a highrise that sent the big ladder truck down our little street. The fire department got sick of this so we updated a few years ago to have heat detectors that are wired into the building-wide alarm but the smoke detectors only go off locally. False alarms have fallen to basically zero, but the downside is that for reasons not entirely clear to me the new system has to get inspected every 6 months, which includes making sure every one of 200 heat sensors is working, so we get days with 100s of very short bursts of the alarms twice a year.