IIRC this is a feature that is on by default but can be disabled when you turn off the phone. I believe it has to be disabled every time you turn off the phone

IIRC this is a feature that is on by default but can be disabled when you turn off the phone. I believe it has to be disabled every time you turn off the phone — it doesn't remember your preference. I don't know if when you disable this feature it actually makes the phone unfindable, or if it just transmits its normal beacon, but with a message attached that says 'ignore me' (which would obviously make you still findable by Apple, if they were compelled).