I'm the one that made that comment. I do take lots of vacations and have a really healthy life outside of work. And I sleep well at night too.

But I always have a 3G-enabled phone near me and I always keep a laptop around. I also have monitoring in place that alerts me in case shit happens before my managers even notice.

This is not about being available 24/7, but about being available when needed. That's in case of emergencies, which by definition are exceptional.

Also, if your customers are suffering because of a problem, good customer service means waking up and fixing the problem at 00:00, regardless of your location.