There were the general rules in the Income Tax Act that various taxpayers had to apply to their particular situations. None of those rules dealt specifically with emissions allowances, so prior to the introduction of the rules contained in Bill C-29, taxpayers applied the general tax principles as they thought most appropriate, because there was a real element of uncertainty.
One of the things we're hearing is that taxpayers want certainty in how these things are taxed. Of course, they were taxed. Some taxpayers took the position they were inventory; some took the position they were eligible capital property. There were issues with each. It is true that the general tax rules would apply prior to this, and this doesn't override that unless a taxpayer elects to do so.
You also mentioned carbon and the definition of emissions allowance applying to carbon. That's what I would call the paradigm example of something to which they would apply, but the definition itself, which is introduced in subsection 248(1), is broader than that. Emissions allowances can be used to satisfy—and I'm going from memory—an obligation with respect to emission of a controlled substance. Carbon, of course, is the classic example, but it's not limited to that.