Utah Supreme Court says suspects can refuse to hand over phone passwords to the police | Other state Supreme Courts disagree and the case would wind up before the US Supreme Court

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.