Why would law enforcement only request this in the iPhone and not in, say, Android or Blackberry or S60 or the plethora of other phone OSs that exist? And why k

Why would law enforcement only request this in the iPhone and not in, say, Android or Blackberry or S60 or the plethora of other phone OSs that exist? And why keep it in a simple standardized db format instead of obfuscated or encrypted?