Specific false-alarm numbers are hard to generalize, since results depend heavily on camera placement, lighting, crowd density and how the vendor defines an event. For a thesis, published benchmark datasets are usually more defensible than anecdotal figures, because deployment reports rarely state their test conditions. Ask vendors for precision/recall at a stated operating threshold rather than a single "accuracy" number, and check whether the reported rates were measured on-site or in demo footage. Also worth noting that event venues vary a lot in density and occlusion, so any single figure deserves caveats.