Some people may have misunderstanding of the confirmation of the current NoA. I think the confirmation is to confirm if the lane suggestion is correct. The car simply says "I need to change to that lane, but I don't need to change it right now if it is not safe, so if you think my suggestion is correct, please confirm, then I will change to that lane when safe." That's why it often suggests a lane change even if there are cars in that lane and the line is read. Don't worry it will hit those car if you confirm. As long as the suggestion is correct, we should confirm it even if there is a car in the blind spot (and the line turns red). What we should do is to watch closely when the car actually starts to change lanes, if it is not safe, we should take over immediately. I think this is to prepare the real NoA where the confirmation is not needed. Correct me if my understanding is wrong.
This is especially true in heavy traffic, it will suggest lane change when there are cars back to back in the target lane. If we wait until there is no cars in blind spot, we will never be able to change to that lane. Instead, we should confirm immediately and let the car turn on the blinker and trying to negotiate, eventually some car will kindly yield and let me in.