depends on when and where.....
I rarely blind call here in KY, but do it ALOT in KS. I don't think it hurts any. Once in KS I had a buck follow 2 does past me in a creeek. I listened for an hour while he chased these does in the creek splashing and grunting the entire time. He was very noisy. I've also noticed bucks that have trailed does past my stands grunting almost constantly. If I'm hunting the midwest and the rut is kicking off then I blind grunt alot. Here in KY I usually only grunt when I see a buck that doesn't look like he's coming in. I base this on the fact that the deer here just seem less vocal. I've heard the "roar" on several occasions in KS, and rarely hear bucks grunt here in KY.