I don't think they care so much about preventing encryption --after all, you can already encrypt your iPhone or Android device, if you really want to.
What they're much more concerned about, IMO, is that this could now be the _default_. No longer would there be a presumption that someone has "something to hide" if they're encrypted when everyone else is, too.
What they're much more concerned about, IMO, is that this could now be the _default_. No longer would there be a presumption that someone has "something to hide" if they're encrypted when everyone else is, too.