Well, here is the good news and the bad news.
The bad news first. Due to the name match, she will ALWAYS be on the list from now till eternity.
The good news is that this is fairly common. The DHS actually have a process for this.
Once, she is cleared she will be given a “Redress Control Number” that she can use when making her reservations.
I believe, she will have to apply for it. It is not automatic but once she is cleared, it is a routine process.
Think of it that your SIL now has a manageable non curable disease. Like Diabetes. Sucks to be her but assuming she follows strict protocol, she will have a healthy life
I’m waiting for terrorists to change their names to “Michael Moore”, “Barney Franks”, and “Michelle Obama”, just to have fun with the list.