Working hours are relative. Our support routinely gets awoken at like 3am because someone in Singapore, where one of our larger customers has outsourced their IT to, just started their day and decided to follow up on a case.
Though I'll agree that weekends should be considered off-limits regardless.
Sorry but for me this doesn't cut it when you have staff and availability zones in every continent on the planet. It isn't some mom and pop shop in one town. It shouldn't be much to ask a company of Google's size and breadth to consider your local timezone for urgent communications.
I mean we're based in Norway, but what if we outsourced our IT to Chile? How would Google or similar know that they need to contact our IT guys during Chilean working hours, and not Norwegian working hours? If it's an invoice that's not paid, well that's done here in Norway though, so definitely Norwegian working hours there...