I did, and I will, but I'm having a reprieve right now. I work in the parts of U.S. Embassies that help American Citizens overseas who are in crisis, and so while I'm not always the front-line person who answers the phone calls (that rotates among everyone, because it's shitty to be woken up at 3:30am for non-emergency emergencies, which most of them are...) if the front-line person can't handle it because it's complex or they work in another area and just don't know how, it's on me.
Technically speaking, I am entitled to overtime/comp time for any phone call I take in excess of 15 minutes. Practically speaking, it's been made very clear to me that if I were to file for that overtime/comp time, I would be laughed out of the office, so I don't.
When I am the front-line person, I do have to be accessible all the time. I am prohibited from being more than X miles away from my work site, and must answer the phone any time it rings, no exceptions. Other that than, I need to be available and if I am not available -- out of town, on vacation, have insomnia and want to take a sleeping pill -- I need to make sure that someone else is. Sometimes, there IS someone else qualified to manage this (if I have great staff) and sometimes the 'back-ups' are not qualified and I take less vacations. On the other hand, I am now REALLY GOOD at training people on what is an EMERGENCY (Death, immanent threat to life or limb, etc.) and what can wait until business hours.
The few times that we've had legitimate crises that ate up weekends, my boss has been great about making sure we got comp time, or came in late the next day or whatever. That, sadly, was under a prior regime... this one has less crises, but is less adept at the HR parts of managing them.