Well..the difference with the roulette thing
..is that those people were using a device (which most are probably not willing to put up the money to invest in) and they were eventually arrested (which will probably deter most of the non-criminal type from trying something similar). The great thing about counting is that its relatively cheap and easy to learn just enough to be a danger to yourself. And the real bonus, you cannot be arrested (unless you have been previously been read the trespass act and it can be proven, etc etc etc).
Of course (as most of you know) for anybody who is serious about it, studying all the books, having a decent sim software, not to mention a bankroll large enough to give yourself a decent shot at it, is not at all cheap in dollars or in hours required to get there. Most of those who attempt counting are not nearly as masochistic, and thus do not succeed. They think the KO book (which by the way, is an excellent book to start, but by far not the only book that should be studied if you are a serious student) and a $1,000 bankroll will be enough to start a career, or even a part-time hobby where they will wind up a little ahead in the long run. It is these lazy un-masochistic people (Wong would probably call them "normal") that allow the AP's to find what few games we still can (not to mention the complete uninformed ploppie).
As for the documentary, thought it was a good one which did a pretty good job of representing the wild swings. Even better, I thought "The Hot Shoe" was an excellent example of how counting wears a person down both mentally and emotionally. The poor case study guy just looked completely exhausted about half-way through the ten day study. Serves him right though, only having a 5K bankroll for a $25 unit and 1-8 spread!
D