My first instinct was to feel bad for a young, foreign player who simply wasn't well-educated about the rules, but it seems more likely they just think they can get away with it. And Marcano definitely should have known better.
The rule itself is collectively bargained and cut-and-dry (lifetime ban on anything you are involved in, one-year ban if not, no middle ground or other punishments, number of bets or $ amounts has nothing to do with it. I assume there are penalties for repeat offenders in the second case).
Rule is also posted in every clubhouse, and I assume both league officials and union reps give a talk every year.
And yes all the leagues work with all the legal gambling operations to monitor activity and vice-versa.