Existing users, 
As you can only change the region code 3 times before are set of the firmware is allowed then a further 3 times before it is fixed forever.
allowing non-admin users to do this eve once is very very dangerous as there is nothing to stop six different attempts to lock out the drive altogether!
DVD RegionCode Unlock
Allow non admins to set DVD region code without a password.
Version: 1.0
Dangerous!
Feedback Type: Commentary
Contributed by: man290663 Monday, January 12 2009 @ 07:55 AM PST
Product Platform: MacOSX
Used Product For: Have Not Tried
Recommend Product: NO
Comments
Dangerous! - MacManux
<<Worst case you have to reinstall the OS. No big deal.>>Nope, unfortunately NOT! Region codes are written back into the DVD drive firmware. So OS reinstallation would not help. You would need to replace the actual DVD drive, no way to get this made undone.
For some DVD drives, there are Windows applications out there replacing the firmware with a hack version that is region free. But only for some drives, and with the risk of permanently damaging the drive...
Monday, January 12 2009 @ 09:43 AM PST
Dangerous! - wonder mac
If you do not want to change the region code on your Mac according to different region DVD, the best choice would be having an external driver. So your copy software must support external driver.As I know, Mac DVD Copy Pro support external driver.
http://www.imediacreator.com/mac-dvd-copy-pro.html#131
Wednesday, July 29 2009 @ 05:39 AM PDT
Dangerous! - Bryan Schappel
Worst case you have to reinstall the OS. No big deal.Reply to This
Monday, January 12 2009 @ 08:22 AM PST