> ...giving parents fines when their children access 18+ content will motivate those parents to parent their children.

And, like most such policies, will disproportionately impact the working poor.

All regulations, because they cause increased costs, will affect the poor the most, since an increased cost will cause the marginal consumer/producer to become submarginal. That is the choice that is made when regulation is enacted, whether the regulatora recognize this fact or not.