Before this week's big Swiss banking leak, authorities had been trying to get information on that opaque and shady side of global finance for decades.

In fact, NSA whistleblower Edward Snowden has previously described his involvement in a CIA plan to recruit a Swiss banker. As described in The Guardian:

CIA operatives were attempting to recruit a Swiss banker to obtain secret banking information. Snowden said they achieved this by purposely getting the banker drunk and encouraging him to drive home in his car. When the banker was arrested for drunk driving, the undercover agent seeking to befriend him offered to help, and a bond was formed that led to successful recruitment.

These dirty tricks went too far Snowden, who had been working as CIA technician:

"Much of what I saw in Geneva really disillusioned me about how my government functions and what its impact is in the world," he says. "I realised that I was part of something that was doing far more harm than good."