We see strong funding levels within pensions as an important parameter to ensure the continued vitality of the promise. We then treat the missing portion, essentially, as a creditor alongside other classes of creditors in the case of an insolvency.
The goal of the policy is strong, well-funded pensions. The reality of an unfunded pension liability in insolvency is that it's an unfunded credit that needs to be paid, and it needs to be paid alongside the other creditors.