Even an nudge and a wink can be industrial action

Under sec 418 of the Fair Work Act, the Fair Work Commission is required to order the cessation of industrial action which is not protected. But what constitutes industrial action in this context?
In Patrick Stevedores Holdings Pty Ltd v Maritime Union of Australia, (2015) FWC 3587 delivered on 29 May 2015 per Cambridge C, the Commission ordered certain wharfies to discontinue a “covert campaign” which consisted of refusing to work overtime which they ordinarily accepted without hesitation due to the attractive rates. The absence of a single wharfie offering to work overtime was enough for the Commissioner to conclude that there was an “organised approach” and that “Consequently, if as part of some campaign of covert industrial action, PIR employees refuse to work overtime, significant disruption and financial impost will be inflicted upon the employer and these impacts will progressively worsen until June 30th.”