> automated electronic location tracking that is to be submitted to authorities

A minor (but absolutely essential) correction - your diagnosis keys are to be submitted to a database, not your actual location data. Only those who observed one of your previous broadcasts will be able to make the connection.

The notion of a mandatory app or device that tracks location in a centralized manner certainly does make me uneasy. Thankfully that's not (yet?) the reality, but (the same as you) I can easily imagine that an appeal to security might be made in the future to justify such a requirement being enacted.

But the current API, while correlated with that issue, isn't actually related to it in a causal manner. On it's own, the published protocol miraculously manages to yield almost no privacy whatsoever. Even better, none of this actually requires cell network connectivity. You could hypothetically manufacture a Bluetooth-only device (thus no location data leakage via the cell network) whose sole purpose was to facilitate contact tracing!

If we're able to achieve effective contact tracing without giving up our privacy, perhaps it will critically weaken any hypothetical future push for a mandatory app or device that could be used for centralized tracking?