I think a number of countries have addressed this question, but we have to remember that only in very rare conditions do we have such major underfunding of companies' pension schemes as occurred after the global financial and economic crisis. As I said before, at that time there was a shortfall of about 25%, on average, in defined benefit plans in most of the OECD countries where these are common.
When a company goes bankrupt with an underfunded scheme, there is, of course, a problem, and some countries--the U.K., for instance--have moved unfunded pension liabilities higher up the priority in bankruptcy. The taxman always wants to come first, of course, and then you have the banks and the bondholders, but they have tried to move pensioners up the range. They have also introduced the pension protection fund to protect those defined benefit liabilities.