Historically we only cared about the local zone, which is where this check stems from. These days we care about updates in all zones, even if those updates dont also have an update for the local zone.

The only function of this flag is to gate a warning, but the text of the warning (and the purpose) don't align with the idea that we would warn on a genuine update solely because it didn't contain information about the local zone.

Though to be clear, my motivation here is to simplify the code.