Nope, they did not use the interface as intended. They requested the interface be modified with 'soft' changes, then exploited the soft changes.
"The pair, according to police, had knowledge of a software glitch in one of the high-bet slot machines. In order to expose the glitch, a special "double-up" feature had to be internally activated. The men persuaded casino technicians to alter "soft" options on the machines, such as volume and screen brightness controls. Such perks aren't unusual for high-rollers, who can wager anywhere from a few hundred to thousands of dollars in one day.
One Meadows employee, who was not criminally charged or accused of wrongdoing, agreed to enable the double-up feature on the machine with the glitch.
Normally, such a feature would allow a player to risk doubling his winnings or potentially losing them all. The double-up feature isn't usually enabled on the machines in part because it's unpopular with most gamblers, who are unwilling to risk large amounts of money.
When the correct sequence of buttons was pushed, the machine displayed false double jackpots. No casino officials noticed because the bogus jackpots weren't being recorded in the machine's internal system.
Throughout April 2009, Mr. Kane frequented Las Vegas casinos, practicing his technique in a "test run," according to authorities, before calling his friend Mr. Nestor in Pennsylvania.
From May 1 to June 15 in 2009, agents said Mr. Nestor joined Mr. Kane in Las Vegas, where the duo allegedly cashed in phony jackpots "over and over again" and perfected a scheme to exploit the same glitch in casinos across the world."
Read more: http://www.post-gazette.com/pg/11004/1115414-58.stm#ixzz1AMex9IZo