They make you sign a statement before you board basically saying you are healthy. All the cruiselinsare doing this now. But who is going to say they aresick if they really are?!
I didn't see anyone appearing sick. They give you a wipe to clean yor hand before every meal and before boarding.
There is a note in the bathroom about safety measures of avoiding getting sick and who to call if so.
I wouldn't worry. Just use good handwashing and you will be fine!
Have fun. I'm ready to go back to WDW!