This does not work on an XS.

Neither do “lock my phone,” “disable Face ID,” or “require passcode.”

Edit: I was wrong - it does work for me when the phone is locked.

Edit: see my parent comment or my response to joshstrange.

Ah, I got it to work. Thank you!

Are you doing this with your lock screen in the ‘unlocked’ state or in the ‘locked’ state? If the lock screen is already unlocked, it doesn’t work (and wouldn’t matter, since whatever adversary you have already has access to your phone). Try it again with your phone locked and the screen off. If it still doesn’t work, report it as a bug to Apple. I can personally vouch for it working on a 6, 6S, 7 and X.

Here are my screen shots:

1. Lock screen in locked state

2. Siri request

3. FaceID settings

4. iOS version/model

I'm not trying to prove you wrong, I really want to see this work and I am trying to figure out what might be different on our phones.

[0] https://imgur.com/a/uil5O7e

Oh I believe you. Do you have your ‘my card’/‘my info’ configured? By that I mean, if you scroll up in Contacts does it show your contact card at the top (and if you ask ‘who am I, does Siri pull up this card)?

Aha! My name DOES show up at the top of my contact but once I click into it it's really some kind of a "shadow contact" or placeholder. It seems it was guessing a bunch of info about me but there wasn't really a record tied to it. I "edited" it, added some basic info (phone number and email), hit save and now the feature works as you described. Thank you!

FWIW I just tried this with my Xs locked and it worked exactly as described.

Thanks for the tip!

Tried it locked and unlocked. No difference.

Follow my comment tree with joshstrange. You basically need a ‘my info’/‘my contact’ card configured.