I never did get the reasons why folks decline housekeeping, but when we go away we don’t want to make beds or deal with emptying trash or dirty linens. The small financial incentive isn’t worth it for us. We do, however, tidy up our things before we leave the room, so that valuables are not visible and there is no reason for anyone entering the room to touch or move our belongings (especially personal items like toothbrushes, combs, razors, etc.)
Regarding the new coronavirus, I think if we instantly knew how dispersed it has been over the past few months we would be a lot less concerned about it. However, I don’t want to catch any virus, which is one of the reasons that we do the 15 hour drive to Disney every winter instead of spending time packed into airports and airplanes with people during cold and flu season; we are fortunate to have the option to drive. However, I’ve never worried about housekeeping—I believe that they use gloves, and I can’t recall any of our stuff being moved, but as I mentioned before, we clean up after ourselves. You could always take a tub of disinfectant wipes to clean hard surfaces just in case.