johndoe@FUBAR.ORG
This would allow her husband "johndoeRegenwassertank" to use any of the Kerberos network applications, such as telnet(1), rlogin(1), rsh(1), and rcp(1), to access her account, using his own Kerberos tickets.
Let us further suppose that "janedoe" is a system administrator. She and the other system administrators would have their principals in root's .k5login file on each host:
janedoe@BLEEP.COM joeadmin/root@BLEEP.COM
This would allow either system administrator to log in to these hosts using their Kerberos tickets instead of having to type the root password. Note that because "janedoe"'s husband retains the Kerberos tickets for his own principal, "johndoe@FUBAR.ORG", he would not have any of the privileges that require his wife's tickets, such as root access to any of her site's hosts, or the ability to change her password.