Final answer:
The question seems to be based on a misunderstanding; the provided texts do not detail an event where Australian prospectors show they are not unarmed to Papuans. Instead, they offer insights into various historical interactions involving exchanges of gifts to establish peaceful relations.
Step-by-step explanation:
In the context of historical encounters referenced in the materials, no specific action is described where Australian prospectors show they are not unarmed to deter Papuans from stealing. Instead, the excerpts provided discuss various historical interactions between European explorers, including Captain Cook, and indigenous peoples. These interactions often involved Europeans presenting indigenous peoples with gifts or showing them artifacts such as swords as a means of peaceful exchange or demonstration, not necessarily as a deterrent to theft. In several accounts, explorers like Columbus gave gifts and trinkets to the indigenous people to create goodwill and to show peaceful intent. These acts often helped in establishing a peaceful trade and encouraged friendly relations. However, there is a historical note where people would take arms to their fields for fear of surprise attacks, showing a contrast between peaceful encounters and preparedness for potential conflict.