I recently learned about selling tradelines. As far as I understand it users with credit cards with long credit histories and large limits sell authorized user positions to people looking to improve their credit score. The authorized user never receives a card, and they are removed from the account after a few months, but in the meantime it helps boost their credit score so they can get a loan at a better rate. My questions are:
1) Is this a scam/legal? It feels like a scam.
2) Why would credit card companies allow this to persist? It seems like it'd be easy to flag anyone who has bad credit and then latches onto someone with good credit for a month.
3) If this is legal is it safe? It seems like the kind of thing that scammers would exploit and somehow end up with a copy of your credit card and make huge purchases on it-- the added insult would be that you wouldn't even be able to contest the charges since they'd be from an authorized user.