We have passports from 2 countries. We don't want them to know we have citizenship in the other country.
We need to leave Country A with Country A's passport, and enter the Country B with Country B's passport. We can't go directly, because the airline from Country A will tell Country B our Country A passport info. We need to go to a third country in between, and change passports there.
What is a good country to choose to go, in between Country A and Country B, that will not notice or care about immigration getting a passport that is different from the passport reported by the check in airline? We don't want a country that will turn this into a big deal, and proactively inform Country A or Country B about our second passport.
I can see existing discussion about travelling with 2 passports, but none of them are concerning how to do it without countries detecting they have 2 passports. With the increasing amount of information sharing happening when flying, I think this new post is required.