I just rented a brand new Ford Explorer and tried on the lane assist and it's the stupidest thing, I would never waster money to pay extra for that "feature"

From what I can tell it doesn't have an actually sensor in the steering wheel to tell if your hands on on the wheel, so instead it judges that by the fact that there is "resistance" or "feedback" from you turning the wheel or slowing it from turning while adjusting to stay in the lane.

However, this means that when you hit a straight stretch of road, and have no need to adjust the wheel physically, it blares a "KEEP YOUR HANDS ON THE WHEEL" warning at you until you move the wheel a little bit. So on a straight stretch of road you have to unnecessarily weave left and right a bit in order for the car to not get pissed at you.

If you don't and the car thinks you don't have your hands on the wheel it just turns the system off. So fuck you apparently, they'll let you weave off out of the lane on purpose if you're having a medical emergency and can't keep your hands on the wheel and relying on the lane assist to slow down safely.