As UNIX system administrators, we constantly have to kill abandoned screen-locked sessions. Obviously, this can be a frustrating task when you're dealing with a headless server and/or all your workstations are being used at the same time. Here is a suggested workaround.
Create an xlock group in whatever name service (files, nis or nisplus) you are using, and then add your login to the group. You should be able to unlock user's screenlocks with your password.
This post is referring to the “lock” on the desktop panel.
Note: Your IT or security department may prohibit or restrict the use of an xlock group.