That is an extremely important question.
Yes, we see systematic under-reporting when we have voluntary disclosure. In fact, academics I know even looked at disclosures from the CDP, the carbon disclosure project —they are some of the best ones we have—and found that there were basic addition errors and so on. We can't trust the information we get from voluntary disclosures.
Frankly, referring back to the comments about costs earlier, because there's no world in which we don't have disclosure, we're increasingly required to do that because of interactions with other parts of the world that already have it. It is actually, in my view, likely to be less costly if we have mandatory disclosure that aligns with what other countries are doing.
Voluntary disclosure regimes that don't agree with one another are a really good way to run up costs and make sure that you get information you can't trust, act on or use as a basis for investment.