I love this campaign and apply the phrase in almost every aspect of my life.
My colleagues don't even bother asking me for a favour when they know what the answer would be. My Aussies boss cringes when he hears this phrase which also means the end of the discussion for him. My wonderful PA gets a head shake and she knows it carries the same weightage as the phrase.
"TAK NAK" - so short and so not negotiable!