Ok, let's give it another try you retard.
When in a game, you choose a weapon with crosshair, now you take a tape and put it on your computerscreen where the crosshair is. Now you switch to the Sniper Rifle and you still see the tape, because it's on your screen. Sniper Rifles usually have no crosshair, so now you got one.
But it is still pointless, because it won't work properly. When you don't scope, the rifle is ridiculously inaccurate. It may sometimes shoot to to the place the tape marks but the bullet is more likely to miss it.