Hi Fido, this script worked for me. Thanks for posting.
Can you tell me how to get it to run on my son's user account please, on my MBP, OSx 10.8.4. He is a standard user, and when he launches the script, it errors out with "insufficient permissions". Using the "get info" right click action, authenticating as admin, and trying to set permissions doesn't work as there is no option for 'execute'.
Regards, Mat