The Disney website says no sandals for the ladies, I did wear sandals when we went to Remy. They were dressy black Dansko sandals and I have worn strappy black satin sandals with heels to Palo. I would not wear my Chacos or Birkenstocks to Remy and I'm guessing Disney is referring to the above mentioned casual sandals.
I wore a dressy summer dress with a cardigan (I get cold) and DH wore a suit.