I’ve mulled/wished for this for years. Also useful at borders, where in the past I have actually been asked (required) to unlock phones and laptops. Generally you have no rights whatsoever there.

Those shadow accounts would need to be ‘lived in’ to pass those border checks. My worst experience was traveling with new, obviously burner devices — border agents were extremely suspicious.

No, but there is at least one app out there that lets you set a panic code that will wipe the phone when used

I had something similar on my laptop with encrypted volumes and duress passwords. So my documents folders were all on an encrypted volume and opened by the standard super hard password. The duress password was much easier and contained a skeleton structure to look legit. The idea was that if anyone brute forced the password it would just find the duress folder first and hopefully no one would look further. Seems like overkill but I was traveling to China for business so necessary. I did however use a burner phone as opposed to my real cell.

I used to have an android launcher years back that did just that thing, actually. It ran different instances of the home page based on what password you entered. You could access other instances when logged in via a 3-finger side drag, but it was able to be disabled. I don’t recall what it was called anymore but I had to have been using it back when I had a Galaxy S8 or even older.