Hmmm... Let me think. Where would a person get such a “device”? :)
According to this article: http://sanfrancisco.cbslocal.com/2013/11/20/lawsuits-prompt-bay-area-sheriffs-to-issue-concealed-weapons-permits/
There are only 1616 CCW permits in the Bay Area.
Good luck legally carrying where the fascists have already won.