It‘s nearly as good as my story. I‘m walking with airpods past my car. The car detects my keys and turns on bluetooth, iPhone connects and thinks it's better to send audio to my car instead of the airpods in my ears. A long and painful connection loss is the result while I walk away and hope that my airpods reconnect. There is no way to set a presedence or similar. These days it‘s even better, the iPhone also switches to car mode and forces me to disable it first.