Users not properly logging out of systems can result in sessions that will never be terminated. To make sure the sessions will at some point be terminated, a TMOUT variable can be set in /etc/profile

case "$0" in -sh | -ksh | -bash)
  export TMOUT

In this example, the value for TMOUT is set to 32400, which is 9 hours. This is longer than a normal working day, so it should not bother people in their work.