Final answer:
Letters found in Roderigo's pocket indicate a strategic approach to concealment, emphasizing the importance of accessibility and the use of cunning methods to disguise the true nature and importance of the letters.
Step-by-step explanation:
Letters found in Roderigo's pocket prove that there was a plan to use them for a certain purpose, and they were not concealed in the usual manner. Instead, there seemed to be an intention to make the letters easily accessible. This method of concealment through not attempting to conceal is suggestive of a deeper strategy.
The excerpts you provided mention various instances of letters and the strategies around them which imply that the significance of a letter can be in how it's hidden or presented, rather than merely its content.
For example, turning a letter inside out, or cunningly placing it where it would not be expected, such as the case in the story where a letter was refolded and its placement carefully thought out. This action made it seem inconspicuous, which proved to be an effective method of concealment.