Yeah, I get why it's in the game. Some players really need an arrow telling them who to guard instead of just remembering who it is? lol.
"Leaving assignment" + "who to guard" arrow is a double edged sword. It helps the super noobs but if more experienced players want to play team defense, it penalizes them and makes your teammates behave like robots who are afraid to leave their assignment and who can only follow an arrow instead of reading and reacting to the action (team defense) on the court.