You know this because? Once stored it can be farmed to anyone with a mapreduce job to spare. Esp when the investigating agency can take some of the bounty, law enforcement can be a nice profit center.
Valid point. We don't know if they're doing that (and I suspect it's probably illegal) on a wide scale (the parallel construction cases appear to be specific help requests made by the FBI/DEA to intelligence agencies), but they certainly could in the future if they're not already.
