interesting
Fragment of a discussion from Comments:Queensland state Premier announces March 24 election date
What I've observed is that, atleast here in Australia, the Premier would usually go to the governor to get the writs issued then announce the election. It's pretty much just a formallity that the writs are issued when requested. (Same thing with the Prime Minister and the Governor-General)
I'm fairly sure there is some law on the books that allows the local government elections to be moved.
And finally, the campaign started prior to the announcement any way.