The key difference to me is that they can't prove that you know your password. What if it isn't you phone? Or you just changed your password yesterday and in th

The key difference to me is that they can't prove that you know your password. What if it isn't you phone? Or you just changed your password yesterday and in the stressful moment can't remember it. It would be fair to punish you for not knowing the password. Since they can't prove you know it they can't force you to enter it. However they can know if you put your finger on the phone. So they can compel you to do it and either it works or it doesn't. Either way not your problem. If it is a warrantless search or not is a problem, but seemingly orthogonal to password vs fingerprint. I agree that they shouldn't be able to look through your phone without a warrant even if it has no authentication.