Hi,
Boy, I'm surprised this post has been up for this long without a reply! This one usually gets the posts flying!
The "signature restaurants" such As California Grill, Artists Point, Citricos, Jiko have a dress code, but it is a suggested dress code.
The dress code basically comes down to: no tank tops on men, and no swimwear on anyone.
You will see people in all types of attire in these restaurants...some in t-shirts and shorts, some pretty dressed up, others somewhere in between.
Disney's version of business casual is not the same as the rest of the world's definition!