I would avoid white shirts though
In 01 - MIL, DS & I all wore matching white Mickey tshirts
The big plate used as a prop in the picture before they sit people down to eat is a hugh WHITE plate. So avoid white if you dont want to blend in.
We do CM for dinner of on the first night of every trip. We ususally go casual, but nice. I like to get the picture they take when you first walk in. I have a collection of them now and I can see how my kids are growing!
Have fun! I get to make my PS in just two days. Makes me feel like the trip is almost here!
We once walked off the monorail in the CR after 6 hours in the Parks to our 6pm Chef Mickey PS.
Brushed out our hair - had our pictures taken by the plate -
and with backpack & water bottles were seated at a table.
We were in shorts and t-shirts.
The food tasted wonderful