Re: You can pry my password from my cold, dead lips.
I think it's quite established in the USA that your password is protected only if the fact that you know the password is in itself incriminating. Not the data on the phone, just the fact that you know the password. If unlocking the phone in front of the judge, then immediately locking it without anyone seeing anything on the phone, was enough to incriminate you, then you don't need to unlock it.
Otherwise, you have the right to unlock the phone without anyone watching you, so you can unlock it without revealing your password.