I have blanket coverage of security cams, costs a fortune, and still theiving is rampant, I followed one of the pickpockets to see how they were managing it with cams everywhere and watched as he stole while directly under one. Then a few mins later a guard walks passed him, tips his hat and kept on going and left him to it. I got sick of manually ejecting them all so went to the effort of covering everywhere in cams, using the terrain circle to set them at no further than 15m radius to make sure no holes in the coverage and it basically seems like a waste of time and money to me.