If you do intentionally hit a batter, dont aim at his head
Throwing at someone intentionally is one thing, but headhunting is a whole 'nother bag. Ray Chapman, a shortstop for the Cleveland Indians in the early 20th century, died after getting hit in the head with a pitch. Until 1971, players were not mandated to wear a batting helmet. With the increase of concussion awareness throughout all sports, headhunting might be the biggest no-no of all the unwritten rules.