Much of the evidence against the "insurgents" at the Capital on Jan 6 came from their own cell phones, including many selfies and pics of their fellow rioters. Simply establishing a separate cellular trunk, which all government institutions have, filtered out the "noise" of non-related activity and identified everyone there who was in possession of any electronic devices immediately.

The problem with sorting massive amounts of data, such as with location detectors, is the volume of such data, which becomes self defeating for any respectable government wannabe dictators. It is so much easier to follow the KISS (keep it simple stupid) principle and use what is available.