An alternate option... if you can't tell them when they log off, you
can tell them when they log on! (Ripped from
http://addict3d.org/index.php?page=viewarticle&type=security&ID=252&title=Windows XP Tweaks and TIPS,
tested on my machine, USE AT YOUR OWN RISK (ie backup your registry...
it worked for me, but I always backup whenever making changes!)).
Assuming you use Windows XP:
In situations where you need users to read a legal notice (or Terms of
Use notice) before logging on, this tweak will create the caption for
the notice.
[Start] [Run] [Regedit]
Go to:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT\CurrentVersionWinlogon
Modify or create a string value of type REG_SZ named
[LegalNoticeCaption]
Type the caption you wish for the Dialog Box as the value of
LegalNoticeCaption
Modify or create a string value of type REG_SZ named [LegalNoticeText]
Type in the message you want displayed in the value of LegalNoticeText.
Exit Registry
Reboot
Voila! You now are notifying every user of the policy for using the
machine, and can include the warning that all files will be removed
from the machine upon logoff.
Hope that helps!