One theme in Sherlock stories is the following. The more extraordinary the facts are, the easier it is to crack the case. This may appear a striking and paradoxical claim at first. However Sherlock’s explanation makes total sense – the more the facts are out of the common place, the fewer the number of reasonable explanations for it, meaning the fewer branches in the detective’s hypothesis tree he/she needs to go through.
This story is a case in point. The shop owner’s experience is indeed very uncommon, funny and borderline ridiculous maybe. But ridiculousness is a good thing for Sherlock. It means that the underlying purpose is strong, and there is a lack of camouflages to hide the plotter’s intention. The phony job is shaped for the shop owner very specifically – indicating they want only him and no one else. The job is ridiculously dumb and highly scheduled – indicating they just want him to be at the place at very specific time, which if flipped becomes they want him NOT TO BE AT HIS SHOP at specific time. Of course the readers are not told about the geography of his shop at the beginning. But when the bank is eventually mentioned, it is nothing but obvious what is going on.
So to be a smarter criminal, consider the following:
- Think of ordinary ways to achieve the “unspeakable” objectives, i.e. try to use those actions of which there are a gazillion explanation and motives so that pinpointing to the desired outcome is impossible.
- Meanwhile, maybe throw out some extraordinary clues for the purpose of misleading, in other words, red-herring. (But this is a tricky one, as a misleading signal is a signal nonetheless, calling for suspicions)
- Last but not least, when thinking about using tunnels, don’t just dig one tunnel with two ends. Always dig a route different from the one used for entering for retreating, if possible.