The only people that I see working 24/7 are those who run their own business, which made sense to me because everyone else has a contract that stipulates the obligations of both sides. Unless that doc says that you're expected to work outside of work hours (which sounds self-contradictory), that's not part of the agreement. I'm surprised Australia needed a law for that
I've been in business for 7 years and fully self-employed for 4 years. Last week was my very first vacation without my laptop.
For the office space - do you mean popping into the office at odd hours, like evenings or weekends? I'd probably be encouraging my engineers to talk to me about why they need to do it and not enjoy their non-working hours. If the work is too much, we solve for that. If they're going all in on something they love, I'll want to make sure they're not on a path to maybe burning-out.
Everything in context.
I can assure you old sport, not being contactable outside working hours has nothing whatsoever to do with requesting flexible working hours. And quite why an employee would like to "use the company office space" (be in work!) outside working hours I've no idea!
I help people settle in Germany, and it's one of the main cultural aspects I cover. The other is how normal it is to take sick days.