Newhavenct raises a good point, and I'd turn it around...
This guy got caught because his method was all the way dumb.
The volume of traffic was so large that it stood out and it seems he made no real effort to hide it.
I've not heard of a case where sophisticated methods were used to take stuff, by 'sophisticated' I mean things you can't do with a shell script and tar.
That leads me to believe that the smarter people who take code aren't being caught.
However I am very explicitly saying this is not a reason to try...
Take the case of GS as an exercise in internal politics, not technology.
How does senior GS management see it ?
0) They see security as a cost, not just that, it often gets in the way
1) But they see now that people are stealing their stuff big time
2) If you're smart enough to be big at GS, you're smart enough to work out that if you catch one person, odds are there's more than one.
3) Security at GS succeeded, and banks are positive feedback systems, so their requests for more money to monitor are much more likely to succeed, and any complaint by stafff that the security stops them getting work done won't just be ignored, they will attract unwelcome and politically well backed attention from security.
. I would have also thought that the security experts at the bank would have been on the look out for exactly this type of thing.
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