I have to assume that tesla's cars aren't confused by those things either, for the most part. The difference is that most car's emergency brake systems act when a driver has failed to respond; the driver and the computer are acting in concert. Tesla has designed and marketed their system as if it worked separately from a focused driver. In the rare instances that their system fails, it is much less likely that the human driver has been paying attention and will brake manually.

I just looked up the subaru system. In the emergency braking case, they clearly claim that their system acts only if the driver has failed to brake. That means, for example, that it will brake much more abruptly than a human would, since it is waiting for the last moment before braking. Their lane following technology behaves similarly. Tellingly, it is called "eyesight", suggesting it is merely an extra pair of eyes, rather than "autopilot", which suggests that it can drive on its own.