[XorNot]

On some level this is why I'm skeptical of all security efforts in the electronic space.

Because if the government or anyone sufficiently powerful is actually after me, the first thing I'm going to do is throw my phone down the garbage disposal and blindly dd all my hard drives with zeros.

[CGamesPlay]

Unfortunately this plan relies on you knowing that they are after you. In the case of a raid when you're not home, you won't have access to the hard drives to erase them.

[mattthebaker]

Tampering with evidence, which includes destroying evidence is also a crime. IANAL so I'm not sure at what point a phone becomes evidence, i.e. once there is a indictment, once there is a warrant, t=0, etc. John Carmack got in trouble for deleting emails in that IP case if I recall. A better privacy feature might be that the phone stores no history.