So yesterday I tried to test the "Find my" offline mode on two iPhones and one Mac. I turned one phone (A) into airplane mode, the second phone (B) is connected to the internet and marked it (A) as lost on my Mac. According to my understanding iCloud should push the lost_phone_key to all nearby iOS devices that send bluetooth beacons to find and lock the phone.
However I could not get this to work. Has somebody tried this? Did it work for you?