un-dedicating a line to a dialer

[Robert Elz]

  > A sensible system will send a HUP signal to the process group when its
  > leader dies, and unless the long-runner has been 'nohup'ed (and its
  > references to the terminal closed), it will die.

Quite true, however, many of your average "long running" processes
ignore HUP signals, so your "sensible system" doesn't do a lot of good.

A better strategy would be to force the terminal closed when
a user logs out (not just when pgrp leader dies, as that overly
restricts the use of pgrps).