I would argue that the two do not have the same carrying capacity for bugs.
A net stays damp longer, and is porous so both detritus and pathogens can hang out a lot longer. My main issue with nets is that they scrape the slime off the fish which somewhat reduces their infection barrier. (The slime that's stuck on the net is heaven on earth for bacteria).
A smooth plastic, food-safe container tends to be hydrophobic. So water beads up and falls off. The dry plastic surface is not an ideal environment for bacteria. Theoretically, virii can stay virile on dry surfaces, but a good washing with soap will take care of most. (Of course one would NEVER wash a net in soap. It would be too hard to ensure that all the soap is gone from a net. Not a problem with plastic).
And finally, I find that transporting the fish in a plastic container leaves the fish somewhat confused but calm. There is no thrashing that is typical of transporting by nets. Perhaps they think they've fallen prey to an alien abduction. :-)
Tim