On and off can mean any number of different things to different people.
To turn a script "off" the simplest thing you can do is add this line to your script
Esc::ExitApp
This will stop your script in its tracks simply by pressing the esc key. Turning it back on will require you to run the script again
To start and stop your script but not unload it you could add a key like this...
!Esc::Pause, Toggle
This will pause your script and restart it from where it left off. So as you can see, On and off can mean different things depending on what you want to turn off and on...
Never assume evil intent when simple ignorance will suffice. Ignorance is an eventually curable condition with the right education. Evil intent, however, is another matter entirely. Scripts are much like children. Simple to conceive. Difficult, expensive, and time-consuming to raise. Often do the opposite of what you expect them to. Require frequent "correction". And once they leave home you can't control them anymore. But you love them anyway.