Water collection on the top is common and has been for many years. Your customer should follow the advice given by the factory tech, although some of those jerks on the Tech Line are blind as a goose in a hailstorm sometimes..
Options for decreasing the amount of water droplets include turning up the water heater to 130o
or above and using a rinse aid in the dispenser at all times. I prefer the Jet-Dry solid basket myself and hang it under the upper rack in a corner. It dispenses a better quantity of surfactant that the liquid reservoir and won't clog up.
The customer can be pissy all they want, as this is not a problem peculiar to Maytag or any other specific brand. It is a product of producing dishwashers with Energy saving qualities that bring about other, less pleasant side-effects. Plastic is porous, and that's that.
If the customers knew the sump holds a quart of water, they'd likely moan about that too