Most of these responses are bringing up things where specific information obtained from the phone could be challenged later if someone tried to use it in court.

Most of these responses are bringing up things where specific information obtained from the phone could be challenged later if someone tried to use it in court. They don't bring up anything that would pre-empt the search of the phone itself, though. See, for example: https://www.forbes.com/sites/thomasbrewster/2018/03/22/yes-cops-are-now-opening-iphones-with-dead-peoples-fingerprints/ https://www.forbes.com/sites/thomasbrewster/2018/03/22/yes-c... Choice quote: And it's entirely legal for police to use the technique, even if there might be some ethical quandaries to consider. Marina Medvin, owner of Medvin Law, said that once a person is deceased, they no longer have a privacy interest in their dead body. That means they no longer have standing in court to assert privacy rights. Relatives or other interested parties have little chance of stopping cops using fingerprints or other body parts to access smartphones too. "Once you share information with someone, you lose control over how that information is protected and used. You cannot assert your privacy rights when your friend's phone is searched and the police see the messages that you sent to your friend. Same goes for sharing information with the deceased - after you released information to the deceased, you have lost control of privacy," Medvin added. So, once again: if you're alive, you can assert your Fourth Amendment rights with respect to your phone. Police will need a warrant to search it. Once you're dead, the only person with standing to fight the search on Fourth Amendment grounds is, well, no longer standing. They can search warrantless.