Bavaria here, and every first Saturday the siren goes off for testing purposes as well. This was supposed to be bigger scale though.

Haven’t heard anything today.

I'm also in bavaria and did hear it. Probably a problem in your city, not in all of bavaria.

I kinda figure that if people heard the lunchalarm going off at a different time, they'd just assume it was Monday noon and it'd confuse the rest of their week.

If I recall correctly in a non-testing scenario the sirens are twice as loud as during a test. Should provide enough of a hint I'd imagine.

Same here. Colloquially, it's the monthly 'Germans invading again' alarm ;)

In Sweden it is the Fikatuta, ie a signal telling that it is time to get some coffee.

(or that the Russians are invading again)

And in Sweden since forever

Actually the same in the Netherlands, except that for a few years we had "silent" alarm tests. This was of course a bad idea (actually letting everyone hear it is quite reassuring, and it's good to know what it sounds like), so this was reverted, although that took longer than it should have.