Nice. So the system depends entirely on transponder?
What will happen when one plane is at the right altitude but report one higher by human or machine error on a day where everyone is flying blind? ...not that we have any blind day in LA but still...
It is standard procedure for ATC to request altitude (or, more commonly, to get unsolicited altitude reports) on initial contact, and to not trust the Mode C data until it can be cross-checked for exactly this reason.
What will happen when one plane is at the right altitude but report one higher by human or machine error on a day where everyone is flying blind? ...not that we have any blind day in LA but still...