Yeah they want to see your Itunes account name or your credit card numbers
Personally I could care less to see that as you can see in game what they spent gold on when you look at buildings, decorations, customization of the character and items. Otherwise it's a who's spending habit is larger contest that the wise would not bother participating in as I got a lot better items that will last longer to spend my hard earned cash on then something elite within a game.