Quite a contentious point I'm sure.
I had a couple of recent experiences which led me to ask this question.
I was in a large local B&M (with a bar) which was pretty packed tbh, almost too many people really (sore throat upon leaving). Even among the thick cigar smoke inside, I could pick out that someone had lit up a cigarette from across the room, I didn't even see them until leaving. No one said anything and it was so busy that I can't say it really affected my enjoyment.
A few days later, in a different establishment downtown in mid afternoon, the place was nearly empty. Just me and about 4 others, again in a large place. A lady came in from the cold, ordered a coffee and proceeded to chain smoke newport menthols. This time is really spoilt the room note, to the point where I tossed my stick early: it just was too distracting.
Their house, their rules, but what are your thought on cigarettes in the B&M?