When I was there a couple of years ago, the casinos were strictly enforcing a rule against "sports clothes" -- that is, sweat suits -- even if they were silk -- were taboo. Also, sport shoes, such as Nike, New Balance, Adidas, etc. were NOT allowed, so be aware of the look of your walking shoes. (I was refused entrance to one casino on Arbat Street because of the black New Balance walking shoes I was wearing. So, I went back to the hotel, changed into a pair of Hush Puppie wingtips, went back & took them for $60 plus a few chips <G>.) Ties and jackets were not required, however.