Oh.... So THAT'S why they always see us ninjas.
In any case. Sounds a little excessive, but I s'pose they need the edge if they're that desperate.
Personally, I play with the realistic textures mod that I believe actually made some of the bushes bigger. Also made weapons harder to see because the ground, trees and bushes have a grey tone over them.
I always say that if you can't kill with style, you might aswell not kill at all.
PS. I have a hard time speaking of bushes with a straight face.