How Does the "Find My iPhone" Mechanism Change When "Lost Mode" Is Activated?

Location tracking is normally only available when the phone has an internet connection. When you put it into lost mode it can use a secondary feature: Find My Network. This is a crowd-sourced tracking method, where nearby iPhones sense the Bluetooth signal from your phone and the nearby phone sends location information (transparently to the nearby phone’s user) to Apple, who then provides this to you. Sort of the way AirTags work.

You should read→If your iPhone or iPad was stolen - Apple Support

Beware of a common phishing scam: You may get a text or email from “Apple” or “Apple Security” (or sometimes “Police”) saying your phone has been found and to click on a link to see its location. This is NEVER from Apple or from law enforcement; it is from the thief or fence to steal your Apple ID and identity. Delete any such message without responding to it. Apple never gets involved in lost or stolen devices→Recognize and avoid social engineering schemes including phishing messages, phony support calls, and other scams

Finally, if you actually could locate it how could that help? Confront the thief? People have been murdered doing that. Ask the police? Unless you live in a very small town police don’t want to get involved with low value thefts that have very little chance of recovery. Your phone is probably already on its way to a repurposing factory in Shenzhen, China.

Re: “… Does activating "Lost Mode" change the way "Find My iPhone" tracks the phone's location? …”

Mr Finch’s comments notwitwstanding (an eminently respected member of this community) …

… not that I’m aware of.

My own — perhaps flawed — understanding is that the Bluetooth-based AirTag-like feature described is the fall-back when the phone is turned “off” or else is “on” but w/o an active internet connection.

Would it be a plausible explanation that the gap in tracking occurred because the person turned on Flight Mode?

Flight Mode? Are you asking about Airplane Mode?

Whoever has your phone would have to enter the correct Passcode to even get into the settings on your phone to make any changes. There is no way that anyone could ever guess your correct Passcode in less than 10 tries before the phone would not allow any more attempts.

So, the answer to your question above would be "no".

The bottom line is that FindMy is intended to assist us when we benignly, and absentmindedly misplace our phones.

As such, it’s designed around the needs of locating a non-moving phone (as misplaced phones don’t walk around)

It simply doesn’t do so well if the phone is “on the move” — moving across networks and “FindMy Relays”— and possibly being turned “on” and “off” as well.

It can easily be defeated by a criminal who doesn’t want to be located. (Plus it’s a bit easier to conceal than say, a stolen car)

It’s NOT intended to be a criminal investigative tool or to allow users to confront a criminal.

Re: “Not really a great "feature"

Indeed.

All I can do from my own “Lock Screen” is toggle the flashlight and camera … and inadvertently interrupt a timer which I might have running 😡 …

… and THOSE only because there seems to be no means to inhibit the “feature.”

Ah, yes. Not really a great "feature".

Bob Timmons wrote:

Ah, yes. Not really a great "feature".

You can only control Airplane Mode when the phone is locked if you have enabled Control Center on the Lock screen.

I know that we will. 🤣

BTW, glad that you found your phone.

That’s a major — and possibly expensive — “stressor” off your plate.