Sydney Roosters have a bye that week. McNamara is the assistant coach there. I would imagine that week was the only one he was allowed a break from his day job to come over here. I would also imagine Wigan and Widnes will have known from the outset when Roosters had a bye (since it would have been timetabled in) so who is to say where the responsibility for the scheduling lies?
I think the word you are scratching around for is leadership. I'm sure many of us have worked in organisations when we know exactly when we can (and can't) book holidays and days off and which areas are off limits etc.