It's rude to use a relative's computer without their knowledge.
Kevin is at his aunt's house, which has his aunt's computer that has unsaved info on it, and has to send an important email.
Kevin wants to send the important email.
Kevin asks his aunt if he can use the computer to send an email.
Kevin logs on to his aunt's computer without asking, closes the open programs, and sends the email.
Kevin's aunt warns him about the open programs, so Kevin sends the email without closing them.
Kevin's aunt loses several hours worth of work from Kevin closing the programs.