To give a EU perspective on this:
We dont ban a HA for "delaying battle" using his main weapon, riding away, shooting, riding away. We do WARN a guy if he rides away to hide or to stay away, NOT trying to kill. If the warning doesnt go through, we KICK. We dont BAN, because no f*** way this is delaying battle.
As long as people are not hiding, and they are not on an unreachable place, they are not delaying, they are trying to take advantage of the landshape and tactics. Banning anyone for doing this is a clear abuse, you just dont want your team to lose because this guy is smarter than you.