Frankly - even when this does happen, it IS an operator error. Your safety feels completely different when the sear has slipped. If the shooter fails to notice their safety throw is suddenly WAY heavier than normal, and fails to understand how their firearm's safety functions, and forces it off anyway, then nobody should be surprised by the Negligent Discharge.
Same issue for a Savage Accu-trigger. If it ever slips such that the trigger blade sear-catch is engaged, it WILL fire if you pull the blade. But instead of being measured in ounces, the blade pull weight will be measurable in pounds...
Neither of these are operational changes a shooter should fail to notice.