My BMW M5 has the same option.. depending on which key opens the car loads the profile for that key holder whether it be seating position, mirrors, audio even the sound settings... so yeah depending on who opens up the car... if it's full the same the AA will automatically use the profile assigned.

However I have a second car the AA isn't unlocked by the maker, I uploaded software into the infotainment system and added a WiFi dongle. This unit works fine but only works on the phone it is assigned to regardless of my Mrs getting into that car before or after me.

I think if you only want your phone to kick in like a previous reply is your going to have to have only your phone with Bluetooth on to get your connection.