If it is a totalitarian regime, they'll just kill you. If you're ever really in such a situation, a blank phone is probably the worst thing you can give them.
Instead, why not a dummy profile that's complete with user activity, social media presence, and showing active harmless use? Why not multiple profiles?
For the rest of us, those who are not spies traveling in totalitarian regimes, what this means is you can hand someone your phone to let them use it. It means you can let your kid use it and not expect to get it back with problems. You can even make the profiles based on the password, so that it only appears to have a single account.
Realistically, the biggest threat is theft. This doesn't hinder theft protection at all. It can still have the same protections, while just offering additional profiles.