The first time I went into a Casino I wore a Suit, with Shirt and Tie etc. BIG Mistake! I looked a real Wally! Didn't do too well in the Tournament as everyone knew I was a Casino Virgin!
Since then however I started to wear more Casual Gear, Open necked Shirt, Slacks or even a decent pair of Jeans, I felt more comfortable and was able to relax, which improved my game play. Some Casino's do have a dress code but it is very relaxed in that most don't like Football T-Shirts Which could lead to Arguments between Rival Fans, but other than that, anything goes!