My data point on this is Aldrich Ames who living way beyond his means for a full decade. All the CIA did was send to agents around to tell him to 'cool it'

What this says to me is that people at his level in the CIA and NSA, etc at the time and probably still are trading classified information to friendly governments and large corporate clients. What the CIA didn't expect was that Ames was so utterly stupid as to be selling information to the Soviets instead of say the French Government, or the someone at a hedge fund, or a VP of sales at Boeing.