Just today, a new moderator agreement policy (now recanted, 10k-only) was enacted, which requires moderators to report users that they find to be underage:
If you find a user claiming to be under 16 and a resident of the EU, or a user claiming to be under 13, escalate it to us through the "Contact Community Team" button [...]
You're not required to investigate users or take further action yourself, but if you come across it, please do escalate it.
Being part of the mod-agreement-policy, moderators are required to follow the instructions there, and not following them is considered a violation of the moderator agreement.
However, this contradicts a previous statement from staff, which states (bold added):
Users and moderators are not legally responsible for underage users and are under no obligation to report them to us. If out of concern you would like to report it, [...]
Why are moderators now required as per policy to report underage users that they come across? Is there a legal explanation as to why SE's stance on this changed?
I'm aware of this 2014 post from a then-employee, which stated that moderators are expected, but not required as a condition of remaining a moderator, to report underage users. However, the new policy requires reporting them. Why?
Update: The above policy has been recanted today, as the team forgot to have it reviewed by moderators first, but the team later intends to enact it again once it's been reviewed. I'm leaving my question open in case the same problem exists in the re-enacted policy.