I have one particular user who's account gets lock out everytime they log
off
I saw this happen for the longest time until I started looking at the event
logs. They would log an account lockout routinely at 1:00 PM or some time
afterward. It turns out our screen saver policy was partly at fault, along
with their continued use of the caps lock key.
The screen saver group policy was to lock the computer when it activated.
So we'd have a user walk away for more than "x" minutes to find their
computer locked. After enough tries they would figure out the caps lock key
and resume their work, but by then they've locked themselves out in time for
the next logon the following morning. Strangely enough, they still had
access to their files, folders and e-mail, which I assumed was because the
connections were already made and not yet broken since the lockout.
As I insisted on keeping the screen saver policy because we routinely have
guests wandering the halls during business hours, the only technical fix to
this is to use Windows XP Pro on all workstations. XP Pro helpfully reminds
its users that the caps lock key is on, whenever a password field is active
and caps lock is on.
The other fixes usually involve dragging the repeat offenders in front of
the staff meeting and berating them in front of their peers. While highly
effective, do this at your own risk.

This is also an effective fix for
users who do silly things like tape their passwords to their monitors.