Context and instilling the logic that fighting skills are for protection of yourself, those who are being wronged and competition in sport is the most important thing no matter when they begin to start fighting.
I think some people dont know how hard little kids can hit. I doubt if the striking is going to do much damage. I have seen kids boxing and kickboxing where all they do is strike and havent seen any long term damage. Post Pubescent is another matter tho.