So far, nobody has really said what value comes from the (presumably illegal, and hence cover-up required) use of IMSI catchers. We've all speculated ("easier to find criminals!", "cheaper to find criminals!"), but what, exactly, is the value to law enforcement? The citizens of the USA are supposed to decide (through their representatives, of course) about what to do and how to do it. Perhaps the tools aren't useful, perhaps they are. Without some knowledge we don't know. The feds need to open up about IMSI catchers.