Definitely, I will use martingale strategy because I know, in the end I will win!
Completely wrong, you forget the fact that all casino has limited bankroll which make them limit max win per single bet at a specific number so even if you have infinite bankroll and you do martingale but you reach the max bet/win limit then you have no option to double the last losing bet.
And upon hitting some thresholds against the casino limits, it will automatically flag his account when it happens.
So, even if in the end that there's gonna be eligible winnings. If the casino declares that some wins are not valid on what kind of reasoning they have.
We've seen many cases that the casinos have declined some specific winnings of their huge gamblers for some reasons. They can just say that there's some anomalies or suspected abuse that has happened and we as users can't do anything against that reasoning.