In all of these cases you really want to make sure that whatever the
user did ends – really ends – by the time he logs out.
Sure, there are valid use cases for that. The admin will probably also
turn off lingering then, right?
So, what is problem with simply allowing screen + tmux continue to run
in case lingering is enabled, by simply letting the usual SIGHUP logic
do it's job for processes which have a controlling terminal?