If you wish to go down the road of claiming anyway then it would be a lot better if you never asked the question and were therefore genuinely mistaken about the rules.
I don' think that ignorance as an excuse will "fly".
If you claim something you are not entitled to, and you are discovered, not only will you have to pay it back, you will pay interest (currently 9.75% compounding) on that amount , plus any penalty that the ATO decides to apply.
As much as I dislike the way the Government spends my taxes, it is preferable to worrying about getting the letter in the mailbox requiring a substantial amount of money sometime down the track.
It is simply cheaper, and less stressful, in the long term to ask for a ruling and take it from there.