Most people like to make sure 'goode time we shalt all haveth'. That is true in the SCA, which has various laws set down to try and make everything run smoothly. A key part of this is making SCA combat safe. Minimum armour standards, requiring all fighters to be trained and then authorised, the practice of calling clear and the magical word ('hold') are just part of the Society-wide regulations.
There is a story that one insurance company assessed that SCA combat was safer than the sport of tabletennis!