I don't deny that this is double dipping, but our intuitions about double dipping might not be universal. For example, in America, it is taken for granted that

I don't deny that this is double dipping, but our intuitions about double dipping might not be universal. For example, in America, it is taken for granted that you pay for both incoming and outgoing calls. Koreans, on the other hand, would find it preposterous. Why should the callee pay, when the caller is already paying for those minutes? It's the same situation, but reversed.