We really don't know but it could contribute to phantom braking if it thinks a car ahead is going slower than it is. Everything is worse at night too. Higher resolution will also let it distinguish mirages from other things better, which is also a PB problem.
It's very difficult to disentangle the effect of perception errors on the policy but no doubt it is potentially a problem. I do agree that policy is worse now than perception.
I think it's fair to look at what the other autonomous driving companies have done---and they have achieved capability Tesla is still very far away from. Of course they use a much more expensive hardware system than Tesla and it isn't sellable to the end user so it's not a bad business decision, but they all use more and better cameras, bigger compute, and lidar and high res radar.