Do you really think that Disney will reopen the parks if there's still a chance the coronavirus could spread there? I don't think they will, because they'd hardly like to be the source of thousands of infections and maybe hundreds of deaths.
So in a way this discussion is irrelevant. The "yes, sure, I'll go back and I'll just be careful" idea is moot. And if you think hand sanitizer, washing your hands, and wearing a mask will be enough to protect you, think again. Unless there's utterly no one at the parks--in which case they'll close them again since they can't afford to be open with 100x the CMs as guests--you won't be able to avoid other people. I live in hard-hit NYC and even here, there are oblivious people, despite all the restrictions, all the news, and all the sickness and death.
So if WDW would open while people are still contagious, for sure there'd be plenty of WDW guests who wouldn't be careful or even aware of what they were doing. And, btw, for those of you who don't realize this, the infection is spread not just by people who're ill but also by asymptomatic people. So just because the person near you isn't coughing or sneezing, it doesn't mean you're safe from catching this.
I want to go back to WDW as much or more than any of you do. And with everything that's going on, I really need Disney more than ever. But I don't need it enough to risk my life--or the life of others--by going there.