Understanding other people can become a tool for obtaining market advantage, and this advantage will be all the greater the worse others understand one another. Of course, to obtain a benefit, you need to be paid for this understanding. This means that a person who understands is interested in finding those who would be willing to pay. Consequently, they must find how these people, who are misunderstood by others, can be useful. Perhaps they possess valuable resources. Perhaps they are damn interesting. Perhaps understanding will sharply reduce conflicts, which is also an obvious benefit. As a result of the action of market mechanisms, we soon see a saturated market of translators, psychologists, ethologists (there are also those willing to pay for understanding the motives behind animal behavior), and so on. Consequently, misunderstanding decreases, globalization processes occur, and the market under conditions of anarchy effectively counters isolation and the preservation of prejudices.
Opportunism is more complex, but we have already encountered similar difficulties when considering how ancap counters external effects. Indeed, a person can easily find economic incentives for aggression against other people or their property. If others consider this aggression more or less justified (that is, they evaluate the subject of the conflict as proportional to the damage the person caused while resolving the conflict in their own favor), they are unlikely to intervene, but even in this case, they may take note that the person is inclined to resolve conflicts by non-market means. Thus, even for a rather clever opportunist who knows how to achieve gain without encountering direct intervention from others, a certain reputation will gradually form, and this will affect their long-term success, or simply put, they may become an outcast.
We cannot accurately predict which reactions will correspond to each manifestation of opportunistic behavior. People may grimace and walk past. They may make a remark. They may demand an immediate de-escalation of the conflict from the aggressor under the threat of their own entry into the conflict. Finally, they may use force without bothering with negotiations. Moreover, all these reactions may be instantaneous or delayed.
And all these elementary reactions under conditions of anarchy and a free market will inevitably combine into spontaneous orders that minimize manifestations of opportunism in society. That is how ancap works.