You obviously haven't thought this through very well, have you? LOL.
What do you think that a boxer is going to do when confronted in a street fight situation? Insist that they bring out a set oz 8 oz gloves & find someone willing to act as the referee? No, he or she is going to knock some fool out. And, if they need to resort to hitting below the belt, following a hook with an elbow, headbutting or damn well biting an ear off they're going to do it.
But, I can tell you from first-hand experience that the vast majority of the time such things aren't needed because after the first shot or two the fight is over.
I've been training in various martial arts & combat sports for almost four decades. I was a pro boxer & I've got black belts in kickboxing & Kajukenbo/Hawaiian Kempo. And, you know how I've won just about all of my streetfights? By using boxing. Usually just one or two right-crosses or uppercuts. On only two occasions out of the eight streetfights that I've had as an adult have I needed to resort using something other than hands. Once it was kicking/kneeing & on the other occasion it was a choke.
So, I'd say that if the only skill that I had was boxing, I'd still have done pretty well for myself.