People finding it fun to kill lowbies are rather rare. Most people will eventually one shot them once and move on because it's rather useless. The zones will rotate from now on so removing temporarily the murder points for a day now and then isn't all that problematique especially since once your out of Tesso the players become scarce.
Personnally i'm rather fond of the idea of making, for the during of the events, each zone a guard free / murder point free zone. "Chaos has spread across Conall's Valley. Right and wrong blur in. The Law is powerless." And in exchange, especially for lowbies, grant them a nice XP bonus if they still decide to go play in the zone or some vanity stuff if they manage during that day to accomplish X number of quests there.