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.
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.
Haven’t heard anything today.