I think it's important to draw a line between whether some of their emissions are off the books or exempt from coverage versus whether they receive some emissions credits for free. The important difference between those two is that, in the system proposed federally, in the system implemented in Alberta, and even in the system that was largely in place in Ontario and Quebec before the changes, the full value of any emissions reduction is still preserved by that system.
If you reduce your emissions by 10%, that just puts either more money into your pocket in terms of the value of the credit or less overall carbon tax bill, whereas if 80% of your emissions were exempt from the carbon price, then you would only capture 20% of the value of your emissions reductions. It's important that it gets preserved while reducing the average cost to companies.