That is a good idea. I read about the idea many years ago, but have not made one myself, despite nearly having a whole bunch of teeth knocked out by the chuck from a large pillar drill. As you rightly point out, nearly everybody will try to over-ride the switch when they are in a hurry.
My humble suggestion would be to make a rough impression of the chuck key from something like epoxy putty, and insert a button switch on the bottom of the moulding. That way, somebody would need to think twice about how to over-ride it.
My two cents...