How did the man at the Termini Station in Rome con us by typing in a number into the ticket machine?

The wife and I recently went to Rome for our tenth wedding anniversary. As is typical of our travels without children, we didn't really leave enough time to get from the hotel to the airport to get back home. We were doing battle with the automated ticket machine at the Termini station when a man approached us and offered to help. Now the con-artist alarm bell should have been going off at this point, but we were really late and so we ignored it. He pressed the buttons and got the ticket that we wanted for the correct price. Only one thing was odd: as part of the booking process he typed some number into the automatic ticket machine. Neither the wife nor I were quick enough to see what the number was for. It was about 6-10 digits and he had memorized it. We can't see how we've been conned here but it must have happened. My wife thinks it was a loyalty card scheme. I'm not convinced. Anyone with any ideas please leave a comment?