I read that NSM can be disabled by simply unhooking the network cable, then using the NSM program link to turn NSM off. I tried this from a standard account, and NSM was immediately disabled. The program warned me that "an E-mail will be sent to your parents...", but yet the program turned itself off anyway. An E-mail notification was sent.
Why would you make disabling NSM so easy? If the network were truly not available (rather than just simulated), clearly you don't need to turn NSM off, because you don't have Internet access anyway.
Why not just have the program say "Sorry, can't verify your password online, so the program will not be disabled", or have the password be resident in the NSM program, on the computer itself?