1. euphemism for a small busybody, frequently mounted on the ceiling, that tattles every time anyone cooks anything or takes a shower.
2. Good excuse to have a migraine.
3. Might even alert peeps to smoke too, if it didn't run its batteries down doing false alarms.
4. Never taken seriously due to false alarms. See also, cry wolf.
The landlord had to put in smoke alarms to satisfy fire code and insurance. The rents had to take the batteries out of the little ijits to preserve our sanity.
The whole complex burned down because a neighbor left the batteries in his smoke alarm, so when another neighbor's smoke alarm went off, he thought it was a false alarm.