That might be a problem in theory, but it's not been a problem in practice for me. I've been on an on-call rota with my current employer for seven years or so,

That might be a problem in theory, but it's not been a problem in practice for me. I've been on an on-call rota with my current employer for seven years or so, and it's never happened that I've lost even a significant fraction of a weekend. Stuff tends to break while folk are working and making changes, and I've lost evenings to serious outages. Issues out of hours tend to be solved by a roll-back, or a mitigation (like draining a region) that lets us leave the fix until regular working hours. Probably the most severely interrupted non-working day was when I needed to take an hour between the main couse and pudding one Christmas day, when I was second line on-call and the person who was formally on-call (who doesn't celebrate) needed a second pair of eyes. While the most severely-interrupted working day was probably the one that included this outage: https://medium.com/@SkyscannerEng/how-a-couple-of-characters-brought-down-our-site-356ccaf1fbc3 https://medium.com/@SkyscannerEng/how-a-couple-of-characters.... I'm quite proud of the response to that, especially that we quite carefully and deliberately stopped after one region was back up, running in a degraded state overnight in order to make sure we didn't burn out our teams by trying to do too much out of hours.