dress code

Is there a posted dress code for the fitness center, or even an unspoken rule? Specifically, can I wear only a sport bra or do I need to have a tank/shirt over it? (I would be fully covered waking thru the ship to get to the fitness center.) Are there free steam/ sauna rooms? Are these in...

I have sensory issues... And I only wear flipflops because of this. I've tried many other types of shoes, but my flip flops are the only things that I can comfortably wear. I just want to know, at Palo on the Disney Wish, if they'll turn me away because of them. I know they're getting stricter...