If you haven't altered, destroyed, or concealed the physical phone in any way, then why would turning it off be considered tampering with evidence? Also, I beli

If you haven't altered, destroyed, or concealed the physical phone in any way, then why would turning it off be considered tampering with evidence? Also, I believe there would be a burden to prove that some material stored on the phone would constitute "evidence." Pretty hard for the cops to do that if they can't get into the phone.