MojoKid writes: We're often told that having a kill switch in our mobile devices — mostly our smartphones — is a good thing. At a basic level, that's hard to disagree with. If every mobile device had a built-in kill switch, theft would go down — who would waste their time over a device that probably won't work for very long? Here's where the problem lays: It's law enforcement that's pushing so hard for these kill switches. We first learned about this last summer, and this past May, California passed a law that requires smartphone vendors to implement the feature. In practice, if a smartphone has been stolen, or has been somehow compromised, its user or manufacturer would be able to remotely kill off its usability, something that would be reversed once the phone gets back into its rightful owner's hands. However, such functionality should be limited to the device's owner, and no one else. If the owner can disable a phone with nothing but access to a computer or another mobile device, so can Google, Samsung, Microsoft, Nokia or Apple. If the designers of a phone's operating system can brick a phone, guess who else can do the same? Everybody from the NSA to your friendly neighborhood police force, that's who. At most, all they'll need is a convincing argument that they're acting in the interest of 'public safety.'