Ah, so now the truth emerges!!!
The forthcoming EBA negotiations!!
It would seem that, as usual at this time of the industrial negotiation cycle, certain controllers take it upon themselves to 'help the negotiation process along', by calling in sick and leaving rosters short, by suddenly becoming aware of their fatigue, by suddenly having an attack of safety consciousness, that will only be ameliorated by a large dose of cash in the next EBA!
Perhaps the Australian Federal Police should be brought in to see if there's a conspiracy amongst controllers - and dare I say, even orchestrated at union level. Not saying there is, boys - but sure smells funny from here in the cockpit.