Exactly, it might work for one person, but not for the other person. I have buddies that are still convinced that they will always end up winning with Martingale. Nomatter what I say or even give my own personal examples, they still think that they will end up in profit...
Martinfail is never recommended to players, but those who are new in gambling and think they can outsmart the casino by methods written on the internet which have constraints that cannot be fulfilled in reality. They forget that the casino is running for years and have been making profits for many years too from the players who lose more than win.
One method to teach them is allow them to use the dummy paper gambling method to play and show that in the long run the balance will turn red.
This is so true. One can only have two things: either they get satisfied with what they have earned in profits OR get their balance in the red. The issue comes when peeps start losing their mind while playing the games. In my opinion this can only come individually. We can not read the books, we can not learn the methods that can make us money. If it is money market we need self control no matter what.
I have good experience with multiplyer of freebitco. I always get carried away with “Active bonus” scheme. I play it for fun and I never chase big winnings because I cant, they got 25x wager requirement. So I only play it softly and try my best to keep my mind cool.

Thats the only way to go with it.