Let’s say I become a citizen of a country that doesn’t allow dual citizenship. During naturalization, new country B tells me I have to renounce citizenship from old country A.
Does that have any effects back in country A? How would country A know? Would country A even care if they found out?
The USA doesn’t care, because they don’t require you to renounce your citizenship, and neither does Canada. Some countries won’t let you obtain a 2nd citizenship, so you must renounce your original citizenship to get a new one.