Daniel de Carvalho, a spokesman for Ryanair, dismissed concerns that extra (or as he put it "superfluous"1) security to its booking system might be needed in defence against possible attacks. He told Der Tagesspiegel that it's up to passengers to keep their information secure, implying it's a passenger's hard luck if something goes awry.

But as web developer Thomas Cannon points out, email addresses are freely handed out on business cards and seldom kept secret. Once an email address is known then it becomes a simple exercise in scripting to try every possible combination of flight for a particular day.

"If we knew someone’s email address and were to write a script that programatically submitted requests to the Ryanair website at a relatively slow rate of four per second, it would take just over 10 minutes to check every flight permutation for a flight on a single date," Cannon argues. "To brute force every permutation against an email address for the whole of next month it would take just over five hours."