Yea mate, bosses on the mines used to say that shit too before a random blow in the bag. Allegedly having a smoke right before it can give it a false reading, same as chewing gum. I have done both just to see what happened and exactly fuck all did. I even blew a lung full of smoke into the one at work and still got 0.000 BAC
I believe it to be a myth.
Besides any device which can be tricked by other chemicals when testing just for alcohol should not be put into use as a means of establishing guilt.