Some believe it's important that the Government have a legitimate Legal Reason, "Probable Cause" to get a Warrant, prior to gaining access to your Call Records. I happen to agree and dislike the idea of the Carriers turning over ALL their Call Records for Data Mining / fishing expeditions. This is precisely what the Founders feared. They won't put a "Voice Tap" on unless they see something in someone's Call Pattern, like calling the Iranian Embassy, or your Libyan Girlfriend.