When you change who gets what, it will change people's lives. Take someone who has four weeks leave, and can take two of those and buy it back. The claim is: 'You don't have to buy it back, so how can you be worse off?' But if I am an employer who sees a benefit in having people work for 50 weeks a year instead of 48, who am I going to hire? I am going to hire the people who sell back the two weeks at a good rate, which basically means people without families. That is going to change the work culture of Australia. I find it ironic that a government committed to family values is enacting this kind of legislation.
You might wonder where to find the game theoretical model underlying these views. For this I need to thank a diligent PhD student of mine -- Martin Byford -- who worked out the bargaining model to analyse the impact of allowing entitlements to be traded. His paper is available here. Utilising an economic model of bargaining (similar to that in my textbook, Core Economics for Managers), he finds that competition in the labour market can mean that these reforms will leave some workers worse off. More importantly, when coupled with minimum wage laws, these reforms may reduce overall efficiency as well. Sadly and perhaps surprisingly, the trade union movement hasn't shown much interest in these ideas even if the business press has (another irony!).
Martin and I published an op ed piece in The Age last year on this topic (for the non-economist, it is an easier read than the technical paper).