It's well known that using cash to pay for a ticket will trigger the SSSS crap. What's to stop a "terrorist" from getting a pre-paid MasterCard debit card at the local 7-Eleven and using that to buy the ticket? That eliminates one criteria.

The idea that someone who uses cash must be a terrorist has got to be the most asinine ideas I've ever seen. There are plenty of people out there that would rather pay cash for things than use a credit card.