[B_s1de]

I agree with the realism thing.
I still play paintball occasionally. The last time I did (at Bigfoot, Lanaudière), some dude was turning every corner with one, shooting through the cheapo wiremesh viewport.
Those shields are wooden plates, small size I may say, and light compared to a real ballistic one I suppose! They ruin the game, even a paintball game.

Unless someone uses it in a Non-Counter-Strike way, I'd probably agree to let 'em use it.