Whilst I don't know of the specific U18 rule for the comm bank travel money card, there is nothing stopping you from going in and getting the card on behalf of your daughter. Just keep in mind that for most part it is a credit card with all the abilities of such, however certain places may not accept them for deposits for rentals. (I was knocked back at a car hire place in the US, not that your daughter will be hiring a car, but could be a problem if she hires any sort of equipment whilst away).
When you purchase them your given two card straight away from the branch, but instead of a name it will have prepaid written in place of a card holders name, so there is nothing stopping you from giving one of the cards to your daughter as there is nothing to verify ownership of the card.
Also the numbers are not raised, therefore it won't work in an old style non-electronic credit card machine. That said, that isn't normally an issue these days.
IMHO that's a bit of a risk, be it she loses the card, or goes on a shopping splurge... :shock: