Are you willing to use escrow? Also, what payment methods do you accept? Lastly, is this legal? 50% off flight and hotel bookings can really cut down vacation costs. I am guessing you use the miles frequent travelers accrue? Anyway, do you have proof of previous happy customers? If you can answer all these questions, you have a good chance at becoming successful here 
I don't think its frequent traveller . Do a search and there are couple other people selling similar services. It is either carding or SE. Couple of people have actually reported that they went to the hotel and cops were called. Not worth getting into trouble for.