i think it is time to add a new dimension to the game.
when a team is engaged in a battle with NPCs anything that is in the battle court or ring should be open to attack and this includes any wizards who is inconsiderate enough to stand there distracting the fighting wizards.
in this way maybe it will be realized the common courtesies are due between each others in game play.
one more thing please stress to inquire about joining a group instead of jumping it.
as you may be one hit from finishing a round when some one jumps in and brings in a new NPC foe to battle. and alot of time they just leave as fast as they jump in leaving you with another foe to battle.