You could do this: if you enable passcode confirmation, type your pass anywhere in the text message along with your text confirmation. If you forget, you get a request to do so.
That said, I like the passcode idea. I know that caller ID is easily spoofed, and so I would imagine that the source ID for text messages can be spoofed as well. Requiring the passcode would prevent this sort of attack.
It's not hard to imagine this leading to trouble as soon as you get into the crosshairs of some internet troll who managed to get your mobile number.