I now keep a Nandroid backup of a blank "fake" OS around on my phone, for emergencies...why? I was detained crossing the Canadian border for an hour as the border patrol read through my personal emails on my phone and who knows what else. If I hadn't supplied the password willingly to them, I'm sure they would have refused me entry, so I couldn't do much about it. But having an OS to boot into on any device that's pretty cleared out and submitting that willingly works much better over denying the password. Of course, if you have any really sensitive stuff, this method wouldn't work super well, as the devices could be searched more thoroughly, but to stop harassment when crossing borders, at police stops, etc. I think it's a good idea.