Boundaryless work is now possible due to technology and globalization especially as mobile reigns supreme. Just because you are available does not mean that you should be working. It also does not mean that others should expect that you’re working.
Fight for an availability policy at work and if this goes nowhere, then create your own. How? Let others know when you’re “gone fishing.” Most folks who are psychologically healthy will understand and respect this fact. There will be some who will be upset but that’s there issue not your issue.
Sleep Tip #246: Fight for an availability policy.