They're probably pretty close to right. When I think back to impaired drivers I've noticed on the road, the first two things I've noticed were inadequate lane-k

They're probably pretty close to right. When I think back to impaired drivers I've noticed on the road, the first two things I've noticed were inadequate lane-keeping and wild/baseless speed changes. Autopilot is good enough to mask those two signals. (I'm not saying this is a good idea; I'm just saying they're probably correct in that it reduces their chance to be pulled over.)