Thorough investigation is almost never required. Their speed plot is the usual zig zag, and then all of a sudden, +50mph. Or heart rate will drop to 80bpm while the speed quadruples. I have flagged a few due to bad GPS data, where their plot is making big jaggy jumps across fields or warehouses. One ride with an obvious GPS glitch KOM'd a segment with a speed of 97mph, because the plot just cut through a series of buildings.