My first impression of the technical paper was that the writer was off by an order of magnitude on the amount of water that can and does condense on inside of, for example, Cessna 172 or 182 fuel tanks in humit Gulf Coast areas, with cooling of air during the night, and water condensing out inside the tank.
. . . Of course that is the main reason that "good airmanship" says, "Top off the tanks before putting the plane to bed for the night (or longer)."
. . . However and notwithstanding, there are times when the tanks may not be topped off and then you'll get more water.
 
These comments don't detract from or relate to Barry's excellent "first take" summary.  I'm simply saying I think the author of the paper is way low on his estimates and desensitizes his analysis of effects of condensation of water out of humid air.