What I meant to say in my earlier post is that seeing maintenance work performed while I visit the parks makes me feel safer and thats mostly because I have over 25 years experiance in just that sort of field. There is another thing I will disagree upon, seeing such things as construction equipment, workers, painting and excavating does NOT detract from a "show" image to me, the parks is very much a living thing that is alive and not a still life caricature of a fantasy world where everything is perfect and never needs work or improvement.
Also yes its more expensive to work off hours plus the additional equipment needed and the materials needed that must work during cooler temps such as faster drying paints. This saturday I needed to repair a hole in some fiberglass of a rear hatch on a Ford Aerostar and the overhead door to my shop will not work at the moment so I did the resin batch and application outside during the day when its only 53 degrees (Alaska summer) the resin was not curing so I had to use a heat gun to accelerate it. Same thing applies to Disney parks, even though a winter florida night in summer can be very warm still its changes the process of many things.
Now what would ruin a "show" would be more flagrant hostile CM's than there usually is, that is what a real problem is more so than anything else.