Jules has walked away from her computer in the lab, without logging off. Later, Trish sits down and, still logged on as Jules, sends inappropriate messages out to a number of students and sends similar messages on the class newsgroup.

                 I believe the mistake that Jules made was NOT logging off from her page or computer and knowing that there will be another person when she leaves. The mistake Trish made was not checking if another person was still logged on to the computer, AND sending inappropriate messages even though she might have noticed it was another person's (Jule's) page or log. Yet BOTH of them made big mistakes. Next time, both should check if they logged of and if another person is still logged on.