When it comes to deciding what kind of weight excuse should have in negligence-per-se cases there is a 3 way split of authority.
AUTHORITY 1: Duty and breach are conclusively presumed or established by the violation of the statute. Defendant has no opportunity to rebut, but defendant can show excuse. Trial goes on to causation and damages
AUTHORITY 2: Duty and breach are rebuttably presumed by the violation of the statute. Burden shifts to defendant to rebut the presumption by showing that defendant acted as a reasonable person. If defendant does not rebut, defendant loses on duty and breach. Defendant may show excuse
AUTHORITY 3: The violation of the statute is merely evidence of the duty and breach which may be ignored by the trier of fact. Defendant can win even if there is no rebuttal
Regarding authority 1, what is the point of showing excuse if the trial goes on to causation and damages anyways?
Regarding authority 2, what is the point of showing excuse after failure to rebut results in defendant losing on duty and breach?