If you are considering zapping players in a dying realm who are trying to keep the game fun admist game-wide declining populations then I think you need to seriously reconsider your policies.
If what was done violates the rules, then those who did it must be punished as laid out in those rules. "But the game's population is declining" or "But I was trying to make things more fun" are not valid defenses.
If you feel the rule needs to be changed, then that is a separate discussion, and does not belong here.