The NBA rolled its eyes and issued him a warning which we assume amounted to "Hey, don't do that, you goofball." Smith looked at that warning, nodded, and promptly did it again in his next game. The result was a $50,000 fine. Yes, a man was fined more than many people make in a year for doing something that usually only gets you told off by your kindergarten teacher.
The best part of the whole debacle was the, ahem, straightlaced language used by everyone involved. The league made a statement, Smith issued an apology, his coach criticized him, and sports journalists had to report on all of it like it was an intense foreign policy dispute and not the latest antics of a man who'd already been fined or suspended for using inappropriate language, getting in an on-court fight, pleading guilty in a reckless driving case, violating the league's anti-drug program, getting involved in an "incident" in a nightclub, flopping, and posting an "inappropriate photograph of a woman" (read: his girlfriend's ass) to his Twitter account. It's honestly kind of adorable that he decided to tone it down and get through the grind of playing for another terrible Knicks team by pulling a troll move that a six-year-old would consider immature.