I don't think the company would necessarily have to tell the employees what the local office hours are. (I mean, they'd probably want to, just as a matter of leaving nothing in doubt; but it would be no big deal.)
If you were born and raised in Manitoba, you are already used to the fact that the local businesses open at 1400 UTC.
Of course, if you move to Ontario, you'll have to adjust that. But then, you'll also have to adjust your internal clock
to get up an hour earlier too. In that sense, it's more natural than the status quo.