Ability to lock the Touch Screen to prevent unwanted touch input

While I was measuring up my Panda Touch panel to make a custom mount for it, it ocurred to me there is no way to lock the touch screen to prevent accidental input.

The proper use-case would be something like a Child-Safe lock, to prevent curious fingers pressing buttons and causing serious issues.
This could as simple as needing to slide a slider across the screen to unlock it, or as complex as a PIN.