Randomization happens when probing for new wireless networks or bluetooth devices. Existing connections use your actual mac.
Re:iOS8 MAC Address Randomization Update
by tkinom on Tuesday September 30, 2014 @01:04PM
(#8389378)
In that case, can they just design some equipments to sniff the existing any connections to correctly ID a repeat customer?
Bluetooth is fairly hard to sniff because it has encryption and frequency-jumping built in. It can be done though, maybe with an UberTooth One or similar. http://ubertooth.blogspot.com/
What's the triggering event for new randomized address for both BT and WIFI? reboot, screen on?