[power-pro] Preventing time & timezone changes

[Graham]

Anything that PP can help with to stop my kids getting around the internet time 
filter by simply altering the timezone / time of  the computer - i.e. locking 
out the Time applet in the control panel?
.
Failing that - how about being able to hide a system tray utility which 
re-syncs the internal clock via NIST every 30 seconds.
Suggestions please!
Thx
Graham