For an example - think back to the woman who was an eyewitness to OJ Simpson in the white Bronco making abrupt traffic maneuvers at a point between the murder scene and his home, moments after the murders are believed to have taken place. She accepted $5,000 from a tabloid television program for an interview weeks after the murders, and with that, was never even called by the prosecution. Her credibility was considered vulnerable because she took money for her story.
Here, it's not a matter of vulnerability it is simple truthfulness. This explains why the stand your ground hearing request was withdrawn. The time to drop this bomb is at trial.
Heh. She'll be in the hospital, I'm sure. But you're correct, it will take a real trial for the lies to have any negative effect. As of now, they're still taking her at her word about what she heard on the cell phone even though she's lied about almost everything else.