Wow, abusable. Crosshairs HELP you aim. Why would you want everyone to shoot terribly?
Do you have a crosshair when your aiming a gun in real life?
Didn't think so.
I could see this being useful, maybe in a CityRPG where you have to actually use the ironsights to aim instead of just cheaping it.
If anything, this would work if you edited a weapons crosshairs, I've seen some weapons not have any crosshairs or edited ones.