the best one is when the mace drives you mad and you kill under the spells effect... sorry Pally you done fucked up
Well, for a paladin to equip such a weapon knowing its effects seems like gross negligence when it comes to potential impact on innocent bystanders, so I think I could agree with this one. Any responsible paladin should avoid making themselves such a danger to others.
Now if they equipped the weapon without knowing what it did, that would be a different matter!