Counter measures
As these methods appear to require the device to be turned on then surely someone will come up will a startup app for jailbroken/rooted devices that will wipe the device if the user doesn't input a specific code within a specific time, or verify the existence/contents of some sort of valid "I've not been arrested/had my phone seized" key tucked away on a quiet server in a remote part of the internet?
Well, thats what I'd do if I was stupid enough to feel the need to keep anything incriminating on my phone.