Moral Guardians (Fantasy Craft, Permanent until movie): There is no such thing as "lethal" damage, it's all just scenery destruction and knocks on the head. All injury-related mechanics are renamed to avoid offending someone: Vitality becomes "Luck", Wounds become "Knockout", Bleeding becomes "Dizziness", Critical Injuries are "Ouchies", and Subdual is forgotten about because it's too weird for children to understand. Characters are automatically "defeated" at 0 "Knockout" and their opponent gets to determine what happens to them. Cheating Death allows the character controller to determine: no voting or rolling necessary (though you may do so if you wish). Replace Grave Wound on Table of Ouch with "Reroll twice and apply both results." Because children have short attention spans Special characters heal all "Luck" at the end of every scene, 1 "Knockout" per hour of rest, and heal "Ouchies" at the end of the scene unless they're "Battered Limbs" or worse in which case they heal in 1d4 days.
SilvercatMoonpaw, who points out you can actually use this as an actual functioning rule