Best clause I've added is "core collaboration hours across all time zones" for 3 or 4 hrs per day & the rest of the day is sanity protected from being expected live interaction time. We enforced this through the single emergency escalation process on-the-side-of-a-cliff-cartwheel which is needed for an out of hours page that required a manager's permission but what you know: 95% of non essential interruptions disappear while maintaining the real need to collaborate.
We ran a 'Consider the Clock' rule, so that all non-urgent messages would schedule themselves to only deliver in the recipient's stated local business hours. We enforced this through 'schedule-send' nudges in our systems and made it a key performance indicator for team leads.