The majority of ticket stock fraud is used for full fare first or business class tickets. The airlines do not require ticket numbers in the reservation for these premium fare tickets until 2 hours before deparutre.

All you need to do is call the airline and make your first class reservation. Then you take your ticket down to the airlines city ticket office and tell them you need to change dates/city pairs/or whatever. They will gladly take your bogus tickets and exchange them for legal tickets. When the airline discovers the bogus tickets, they go after the travel agent where the blank ticket stock was sent to and charge them for the full value shown on the ticket.