Hi hobbya,
Most excellent explanations 
, Most like me are familiar with only the basic scan and connect , I like the other options though too. Reminds me of UDP a connectionless protocol Vs. TCP . 
Passive scanning (broadcasting a status)and the ability to make a connection to a specific peripheral when needed. Would be the optimum for my application, that would also give me access to more numbers of peripheral’s. I might be showing my age but this BLE acts like CDMA connection kind of LOL.
You point out the main concern about missing an alarm (motion alarm) in my case the Peripheral currently has a read /notify connection if the alarm flag changes it’s almost instantons. You already see the problem (you have to be connected) with this Nicer Passive and Active scanning with data approach allot more flexibility maybe on multiple devices.
Wow, lots to ingest here but Steller work for sure, I’m stoked to try and implement this technique I wonder if you can switch modes is possible? and thank you for responding and sharing of this great knowledge.
GL 
PJ
