I don’t know that there has. From reading the comments on the post I linked, it seems like it’s the government that pays for the temps, since they are the ones giving the leave? Or since the person taking the leave doesn’t always get paid their full salary (Canada), part of the money they aren’t being paid pays the temp and the rest is the government? So basically, the company only pays what they would normally be paying and it’s just allocated differently while their employee is on leave.
Most of the rhetoric I’ve heard is just “we need to do this,” not so much “here’s how it needs to be done.” But I’ll be honest, since I’m not a parent and hope to never be one, it’s not an issue I’ve paid that much attention to.