All the restaurants in the parks are casual dress(shirt & shoes required), among that the majority of the people in there will have on shorts, tank tops, and flip flops. Youre in an amusement park after all. Shorts and tank tops are the norm at MOST of the resort TS restaurants also, esp. the character meals. The signature restaurants are the ones you may feel a little more comfortable if you dressed a little nicer, though I still think the only restaurant with any real requirements is Victoria & Alberts...