There needs to be a rule. If 95 percent of batters never follow thru and hit the catcher then the few that do need to change there follow thru
DS team was playing in LL regionals last year and their leadoff had a tendency to let go of his bat more than throw it. I don't believe it ever hit anyone, but it hit the fence hard a couple of times. I'm not sure if it's an actual rule or not but the umps did warn him and the coach in more than one game that if he did it again they would toss him.