I voted "Nothing" simply because I believe that Disney will not open the park(s) without taking every precaution imaginable to keep them clean and safe for their visitors. That said, I would trust the visitors less than Disney itself, so that would be my concern.

So far, I have heard of no problems with the 'phased' opening going on at Shanghai Disneyland, so expect that these same measures will be taken at the other Disney parks as well. (Of course, can you take any information coming out of China at face value?)