I just realized this recently, since I lost my iPhone. I might need a little clarification, though. Maybe it's alright.
When you put your phone in lost mode or make the sound go off, if someone finds your phone, they could simply turn off the wifi and cellular from the lock screen, effectively disabling "Find My iPhone". They could make the airplane mode button un-touchable when the phone is locked. I guess that could be a fix.
When you put your phone in lost mode or make the sound go off, if someone finds your phone, they could simply turn off the wifi and cellular from the lock screen, effectively disabling "Find My iPhone". They could make the airplane mode button un-touchable when the phone is locked. I guess that could be a fix.