I'm going to go with the whole "If you don't see the body, he/she ain't dead" trope on Black Mamba.
She sent the message thinking she'd be dead, but there's no conclusive proof one way or another... Assassins Primer certainly indicates that either she's still alive (I'm leaning towards this given the whole comment about people trying to kill her), or someone else has her nick. Alternatively, Assassin's Primer was indeed written before Storm Front, at least in-universe...