My Discover card was preapproved with nothing but au history that was 6 months old. I got a Bloomingdale's card with a $1500 limit with that au history 1 week later. My whole profile and DW's came from au accounts in my siggy that were opened last year.
Just take CALCULATED inquiry risks based on what you see on this forum. Have your sister STUDY other peoples results with credit history and scores comparable to hers. Once she finds a match go for that card.
If she is into it, your sister can build a truly remarkable file. Have her pay the $24.95 a month for the real Fico scores and use Credit Karma to see weekly credit reports. CK scores tend to be much lower than actual Fico 8's.
