The larger issue has nothing to do with TSA, it has to do with any chance encounter with a law enforcement agency and that could happen for entirely chance reasons having nothing to do with her, e.g., she's a witness to something someone else does and the cops need to track her down.

BTW - It's completely erroneous information that TSA can't check warrant information. It most certainly can. Not relevant to OP's question, but it, of course checks warrant information on every Pre-Check applicant (as one of many, many examples).

If you are a friend, you will advise her that whether she does it immediately, she should soon enough get this mess behind her. These things never end well.