A moderator on a Stack Exchange site can record themselves as absent or inactive. Currently the status changes independently for each main site and the corresponding Meta.
I, myself, had taken a vacation twice on the main site, but never noticed that my status on Meta didn't change. In my opinion it's not quite possible that a moderator takes a vacation from moderating the main site but stays active on Meta. So the status should change for both main site and its Meta at once.