No reasons given, I just went for a cig at the grounds where I did previously and I found that the gates locked and the stewards saying they didn't let anyone out any more. Some have really daft arrangements, Peterborough have no smoking anywhere within the ground, despite there being an open outdoor area at the back of the stand (though everyone seems to ignore them there) and Ipswich have an open outdoor area next to some stairs at the away end, but won't let anyone smoke in it.
I liked the copper at WBA when we won 3-0 who said, when someone remarkedthey were pleasantly surprised that you could take your beer out and have a cig at half time,that they only did it when there was a full away allocation due to the fence's position at the back of the stand, "so if you know any West Ham fans you can point out that you went outside for a smoke whilst they couldn't".