Relatively cheaply, you can buy +1 body armor with the spell storing enhancement and a +1 shield with the same enhancement. If an adversary strikes a player character, do both stored spells afflict the attacker? With a wand of Touch of Idiocy (4,500 gp) a PFS paladin could load up her armor and shield, provoke spellcasters (e.g., Challenge Evil, Compel Hostility, or Knight's Calling) and ruin their day. For two prestige points, a wand of Touch of Gracelessness would work well in nerfing dex-based sneak attackers. Ability damage doesn't get amplified if the attacker confirms a critical hit on a pc with a triggered stored spell, right?
