If you were confronted with a combat situation, a heavy blow with a sharp hawk will cut through any scabbard or scab designed to protect the user from the sharp edge unless the edge of the scabbard is reinforced with rivets. Maybe I'm wrong, but I just can't see anyone in any era running around with a naked sharp blade exposed in their belt, if that were the case, there would have been no need for knife scabbards, just tuck it in your belt. A pike or lance is another matter. During Colonial and frontier times, more died or were taken out of commission by disease and self inflicted injuries than direct combat. Gangrene can be a beitch.