Oh. And you think that if Cloud and Tifa didn't at least have some knowledge of each other that Tifa would have come to the playground that night when Cloud announced that he was going into SOLDIER? I don't know about you, but if I was Tifa, I wouldn't be caught with a guy I didn't know at a playground at night just because he asked me too. They had to have some trust towards each other, and trust is only developed through friendship. Thus, Tifa and Cloud very well could have been childhood friends.