I don't think any degree of citizen carry of any weapons is going to stop all bank robberies, muggings or pretty much any specific type of crime. In the "Old West" where many people carried firearms or had often both a rifle and pistol near at hand, criminals still robbed banks, trains, stage coaches, etc. Citizen carry of any type of firearms, of any class, only equalizes the playing field and increases the likelihood of citizen survival. In enough numbers I think it is a distinct deterrent to petty criminals who want to steal a quick buck. But the hardcore criminal types have been with us for millenia and aren't going away.