I booked 2 FFns for the one night at sydney PH for my birthday this year and 4 weeks later-before the stay I had an email from GP saying that If I did not call them within 5 days and give them another GP account for the second FFN(even though I was owed 3) that they would go and take 15K out of my account as I could not have 2 FFns on one night.
So unless things have changed be careful!