&gt; They can subpoena the data and throw the person who controls the key in jail until they release it<p>I think, a lot of the time, they want to read data from a device owned by someone who&#x27;s not jailable any more—i.e., dead people.<p>Reading data off the phones of murder <i>victims</i>—the activity you&#x27;d expect &quot;digital forensics&quot; to properly refer to—would be pretty useful, if it were possible. I imagine a lot of police work has gotten harder in the move from &quot;little black books&quot; and feature-phone contact lists to everything about a person&#x27;s contacts&#x2F;calendar&#x2F;call history&#x2F;etc. being on an FDE-ed smartphone. Manufacturer key escrow services seem <i>almost</i> sensible in this light.<p>The other use is in reading data off devices of someone who&#x27;s already dead because law enforcement just killed them. I can see both good and bad outcomes of that: if it were quick to do, it would help to map e.g. a hired hitman to their client, or a gang-member to the gang-leader. But it would also encourage&#x2F;enable &quot;shoot first, ask questions [to devices] later&quot; tactics, which is just plain horrible.