Consequences of violating informal rules
There is no written rule against a basketball player slapping the court floor. But there are consequences of violating informal rules. Here is a fun example from the Ohio State vs. Nebraska men’s basketball game. http://www.sportingnews.com/ncaa-basketball-news/4695684-jae-sean-tate-floor-slap-video-ohio-state-nebraska-highlights-tai-webster