By false positives I meant non-firearm objects which the robot recognises to be firearms, and incapaciting brought tasers to mind.

I am probably looking at this problem through smaller-and-safer-country specs, Here police shootings are really rare, but so are other kinds of shootings. I thought of bots with high mobility due to the recent advancements in that sector, which would in my opinion make much more sense here than installing dozens or hundreds of stationary devices in every public space.