So this was a little predictable:
here and here.
One would like to think that constitutional challenges like this are a waste of time. The government generally gets high quality advice on these matters and would seem well equipped to adjuge what changes are likely to pass constitutional muster.
Sidenote - my all-time favourite Boston Legal quote:
Even more so (ready yourselves for a bombshell) governments can sometimes take a "Let's just see what happens!" approach to controversial laws.
I don't know enough about NSW Constitutional Law to have an opinion as to whether the laws are likely to be struck down in part or as a whole, and I'm not going to try and offer one. It will be interesting to see what kind of arguments the unions are able to advance as to why they should be able to pay those enormous affiliation fees to the Labor Party.
I think it is safe to assume that the O'Farrell government will be prepared to throw large amounts of money in legal fees at this case to try and make sure the laws survive.
This action demonstrates just how concerned the union movement is about these laws. It was argued during the hearings on these laws that companies will simply encourage their employees to make donations to sympathetic parties (ie the Coalition) - in theory nothing prevents the Unions doing exactly the same thing.
This litigation is going to be expensive for the Union movement - in fact, it will be very expensive. In short, it's pretty clear they are worried.
I imagine this pleases O'Farrell greatly.