I wonder the same about leaks like the Snowden leaks. If Snowden could do this how many other people get access to the same data and use it for their own purposes be it financial, political or both ? My guess is a lot.
* https://en.wikipedia.org/wiki/Aldrich_Ames
* https://en.wikipedia.org/wiki/Robert_Hanssen
There may very well be people who are getting away with doing it now, but the leaked data eventually winds up being used which is how you get caught.
2 things that stood out
> Hanssen [...] is serving his sentence at the ADX Florence, a federal supermax prison near Florence, Colorado in solitary confinement for twenty-three hours a day.
The guy made a deal to avoid the death penalty, but from what I've read about solitary confinement this can't be much better.
and this:
> https://en.wikipedia.org/wiki/Aldrich_Ames
>U.S. mole hunters investigated 90 employees at WTC for almost a year and came up with ten suspects, although the lead investigator noted that "there are so many problem personalities that no one stands out"
Now take a highly ranked powerful machiavellian person, and the scenario suddenly seems very likely.