It doesn’t really matter. You’re submitting to a search by handing anyone an unlocked phone.What top secret information do you people keep stored on your phone that you're afraid a cop will access and somehow monetize at your expense?
Oh you got a text message from So and so 5 minutes ago while you were driving? Did you read it while in motion? Etc etc etc
In the right or in the wrong, it’s still submitting to a search.