I am aware that there seem to be two shortcuts for disabling the keyboard. The first being hitting the option key 5 times, and the second being control-f1. However, neither work for me. I have enabled both the setting that allows the function keys to be used as function keys and the control-f1 shortcut. Why can't I disable my Macbook Pro keyboard with a shortcut?
It would be interesting to know where that information came from, as, as far as I am aware, it is totally incorrect.
These are Accessibility Controls...
Opt x5 is to enable Mouse Keys; that allows your 10-key pad to act like a mouse.
Ctrl/F1 I think you are confusing with "Full Keyboard Access" which allows more complete navigation using only the keyboard.
It Toggles between this :-
The only way I know to actually disable it is to use a utility called KeyboardCleanTool [freeware]