That might be their surviving usage, but used to be small town whistles/sirens were used daily to tell workers when it was lunchtime and quitting time. The practice was still common when I was a kid, but it's a pretty rare town that still does now that everyone wears a watch or carries a smartphone.
In Japan, large outdoor PA speakers play music at 5 PM every day to remind the kids who are out playing to come home:
This article explains it:
https://blog.gaijinpot.com/tokyo-5pm-song/"The beloved music is used as both a daily safety check to ensure the broadcast system and speakers are working correctly, and also to remind children that playtime is over and that they should return home before dark."
And as for the tsunami warning sirens on the Pacific coast, Cannon Beach, Oregon uses the sound of a mooing cow to test the warning sirens, so that people won't confuse it with an actual emergency. It's so distinctive that tourists actually come to visit just to hear the cow siren!