NRPs and maintenance payments

[ConferencePear]

This is prompted by another thread on maintenance payments by NRPs. I’ve heard so many times of NRPs that they are not willing to pay for the RPs fancy clothes, hairdos, gym club memberships and such like in complete disregard of the fact that the money is meant for the children.
If they really meant what they said they would surely set up a bank account and give the children the money they owed them when they reach eighteen. I have never heard of this being done, I wonder if anyone else has ?
It seems to have become socially acceptable in the UK for NRPs not to pay which is simply not the case in many other countries. Am I being unreasonable to think that we should accept the status quo or should we try to get a more just solution ?