Not a formal legal defense recognized by statute, the "SMIDSY defense" is the common excuse that a driver "Sorry Mate, I Didn't See You" after colliding with a motorcyclist. The phrase comes from riding culture, but it points to a real problem: a driver may look in a rider's direction yet still fail to register the motorcycle because of inattention, speed misjudgment, visual clutter, or poor hazard perception.

Practically, the phrase often comes up after left-turn crashes, lane changes, or pull-outs from side roads, where the driver claims the motorcycle was not visible. That statement does not automatically avoid fault. A driver still has a duty to keep a proper lookout, yield when required, and operate with reasonable care. In a motorcycle injury claim, the issue becomes whether the driver acted negligently, not whether the rider was memorable or easy to notice.

In Alaska, fault is usually analyzed under comparative negligence. Under Alaska Stat. § 09.17.060, a rider's compensation can be reduced by that rider's share of fault, but a driver cannot escape liability just by saying the motorcycle was unseen. Evidence such as skid marks, sight lines, lighting, helmet or reflective gear, and witness accounts may matter. On rural highways where visibility can shift quickly because of weather, dusk, or even wildlife hazards such as moose crossings, the "didn't see" explanation is still judged against the driver's duty of ordinary care.