Anyone can buy a ballistic vest, and Evan is clearly shown wearing a ballistic vest carrier (though yes, it is possible that there are no plates inside). However, given the way that she's drawn in comics such as #4939, said vest is both far too low on the chest to offer proper protection (I mean, not that AIs have a heart which renders the whole exercise kind of pointless) and in a position that would crimp her breasts down in a fashion that, assuming anything like a human's nerve-structure, must pinch unbelievably brutally.