Well, I think the people that figure out gambling are truly few and far between, but I do believe that some people are fortunate enough to flip the odds somewhat.
I am trying a roulette system and I have the statistics others claim to have produced. I will be playing for free for sometime to see if I can get similar results. My personal theory is if there is a good system, it doesn't work for gamblers. What I mean is it won't work for true gamblers, with the gambling instinct. Such folks will put too much faith into "luck" (don't believe in it--gambling is mathematics and probability) or will deviate from the system or game plan when things go really poorly or really well.
I then you find a system or work on developing your own and issues come up. I thought I had a good system and, upon studying it, realized I made an error in the probability factor. Originally, I told my best friend about the system I came up with. Within two hours, he was up $2,600 while playing for free, he told me. Then, then put in $500 of real money, got knocked down to $200, then cashed out when he managed to crawl back to around $450. In later discussion, he told me while playing roulette (practice), he got cold and realized that black was long overdue to hit and bet $1,000 on it. He managed to hit and was up $1000. The problem is when he was playing for real money, he couldn't handle the pressure of a few losses and resorted to playing Martindale, which any experienced roulette player knows is a long-term guaranteed loser. He played it ultra-safe. Well, what good is it to "test" a system making some ballsy bet that you would NEVER actually be willing to do with real money?