[Request/Idea] Warn when a BLE scanner device does not have an Area

[jeremysherriff]

Is your feature request related to a problem? Please describe.
I've been chasing my tail trying to figure out why one ESP32 BLE Proxy doesn't appear to report my cat - the issue was quite simple in the end; I had not assigned an Area to that ESP32 device in HA, so she was being reported as unknown location which was indistinguishable from when she's away from the house.

Describe the solution you'd like
Wondering if there might be a simple and noticeable way to warn the user when a BLE scanner device was missing an Area

Describe alternatives you've considered
I've considered doing everything properly all the time, but my wife advises I should try to limit my daydreaming and stick to reality 😅

I wonder about the possibility of reporting the device's Area differently for "not seen by any scanner" versus "seen by a scanner with no Area assigned"? Technically both are unknown but they are unknown for different reasons. "Unassigned" might be a suitable word?

Additional context
This is totally a self-own in terms of my issue with one out of 6 BLE proxies, but I'm assuming that others will have done the same at some point.