People could send a text message with the code and get a message back confirming that what they bought is listed in a database.

VOA: special.2010.03.01

"We're working very closely with Interpol," "They are in the process of establishing what is called the Dangerous and Disruptive Persons Database which will assist us in identifying people that may pose a potential danger to the tournament as far as organized fighting or hooliganism is concerned."

VOA: standard.2009.06.12