My favorite B&M allows it. If I had a vote I'd vote against it but I can live with it to get the awesome atmosphere and service they offer.
The other place nearby does not allow it, but that is literally the only thing I like about the place. They're horrifically overpriced and they follow you around in the humidor like they just know you're about to swipe a dozen sticks on your way out. Screw them. I'll deal with the cigarette smoke. There's not that many who do it anyway.