I think I get DB's point here, OTH. We all lose in our training, if we practice full-resistance against people our skill level or higher. Sometimes they'll best us. That's part of training with resistance. And there, losing is a good thing - it's something we can learn a lot from.
I also understand your point, I think. When training SD, you can't afford to lose the encounter, because on the street you don't know what the consequences might be. So, we take a different mental approach when we're testing/validating our SD work. And since we don't need to score points - don't need to win - we may take a different tactical approach, as well. My first NGA instructor started his career as a cop in NYC (later, and still, teaching DT). He always told me when he had a physical altercation with someone, he was focused on not losing. When he retired from being a cop (and then retired from being a reserve officer), he was "undefeated". He was never looking for a "win", but just to avoid losing.