I answer emails and slack whenever I can. On the flip side, I get work from home privileges, I show up when I want, I leave when I want, and I get put on exciting projects instead of boring ones. People who don't check their phones after-hours cannot be trusted to lead projects with demanding clients. I typically don't bill time until my laptop comes out.
I'm two-minds about this. Companies really do abuse their employees and try to get all the work they can out of them. This is a problem that leads to abusive employers. But employees also look for ANY entitlement they can receive, whether or not it is useful to their professional development. This is also a problem that leads to lazy and useless employees. It's sort of a feedback loop. It's also probably very different outside of my field (and probably most people's field on this site), which is software development.