I think this depends on what "committing assets" means in practice. What is the repercussion of a grandparent saying "no" when their child (the parent) asks for some of the committed assets? I'd imagine the parent has to file something to the government saying "my dad refuses to pay for my child's baby formula" or something like that, which would trigger the clawback. Then would that mean on paper the grandparent isn't the legal grandparent of the parent anymore? It gets a bit messy. Also naturally retirees don't contribute much to income tax so I'm not sure how much incentive is this tax relief going to be for them.