Our kids often get cash gifts for Christmas, birthdays etc and Catholic sacraments tend to be very good earners for the kids
It's simple to get an account set up and lodge as and when gifts are given. We actually sometimes get asked for account details for direct lodgement to make it easier. And believe me kids are excellent record keepers themselves, if I ask to borrow from their cash stash for incidentals they make sure i return it! So no excuses for this case, they clearly wanted to transfer money and made up reasons why after the fact.