The effectiveness of the Lantern Shield in real combat is questionable but in the context of walking around a dangerous city at night it does warrant some interesting conclusions. First off, it was probably very ominous looking and any would be robber was probably inclined to just move on to the next victim. And if a combative situation arose the whole contraption was probably reasonably effective at staving off injury much in the same way as a porcupine does! The addition of the lantern was also a strong deterrent against attack because any nighttime robber would just avoid the illumination and exposure. So as a real weapon it was probably not very good but as a deterrent it was probably reasonably effective. Any robber or ruffian seeing someone carrying this thing would probably just move on to the next victim.