This can help, but there are risks involved. Such as, if you are the AU on someone's card, but they do end up being late, your report will show the negative history, or even if they just want to carry a balance for awhile, this will lower your utilization. I have heard it is easy to 'get off' the report if needed though. Also, if you are the person that is allowing someone to be the AU, make sure they will not run up your card! :)