Thanks for fOmey, who discovered a broadcast that occurs when the GEAR is outside of LOCKING Proximity.
Because using Bluetooth Connection Status is NO good, it remains connected for too far a distance that by the time the Bluetooth LE disconnects, you're already 10s of meters away from the phone.
The unlocking Proximity triggers when you are just 1 meter away or so.
Hmmm I had it ! For the life of me cant remember what it is tho.. ill have a look for you now.
This appears to be the broadcasts (unconfirmed tho!)
Although if you want to just detect if the gear is connected, the easier way to do it is to check the bluetooth status... State -> Net -> Bluetooth status.. I like to use the MAC address as the identifier.