This is a very good example why you should not let anybody to identify you. For example if you have purchased a ticket for the price X then it is a clear ident

This is a very good example why you should not let anybody to identify you. For example if you have purchased a ticket for the price X then it is a clear identification that you are more likely to pay the same amount. The more information you are leaking about yourself, the more unfair everything is going to be for you.