1)i don't think it's illegal

2)that is just the game (no greater purpose or meaning)

3)If you are in the first stage of placing arrows, you can't take down arrows. There can only be a total of 3 team arrows on the sign in opposite directions of the actual sign's arrow, i.e. at a sign like "Paramus ->" you can place a left, down and up arrow. But strategically you don't want to put your arrow on a sign where there is already a different team's arrow, cuz if a third team comes along, they would have two arrows at once.