I consider the auto loss to be a bug, rather than something that should be a suggestion. If you're properly knocked out (e.g. through a bit of "reinforcement" when out, I don't think there's any need for a rope.
It can also be noted that the auto loss description isn't correct: I had a character with a low pain threshold who was knocked out by a lucky arrow in a fight, woke up, went to pick up spare gear, returned to the tile where the fight took place, zoomed in, and the fight resumed. It seemed everyone (henchmen, dog, and robbers) were frozen in place during my character's travels (not very far, as the homestead was just a few kilometers away), The resumed fight was won, by the way...
Thus, your robber most probably didn't kill everyone, just took advantage of a momentary lapse of observation to perform a few impossible feats of stealth.