I tried several seasons with a few of these sets, and never had a set visited. I remember reading this too, and thinking to myself about how curious coons are and how this set might work on that curiosity.
I really think that the conditions would have to be just right, too. Maybe a decent full moon with good light to reflect off that pan, fairly clear water for the low light to penetrate, and the pan sitting just below the surface, too.
I never could get the right combination on it, so I never had much luck with the shiny pan-type set. I haven't tried the rubber crawfish trick either.
I really think that it could potentially work. Coons, although having somewhat poor eyesight in comparison to some other critters, do visit pocket sets. I think the visual is important with them every bit as much as a decent scent and trap placement.
I use a lot of "white objects" when I land trap coons. Maybe a crumpled styrofoam coffee cup down in a dirthole, or I scatter some white paper punch confetti around a set, or I've even used a can of white Christmas Tree flocking spray and sprayed the sides and top of my pocket sets and dirthole sets to make the dark hole stand out more. It seems to work on coons pretty good. Eggshells scattered around (where legal to do so) at a set works good too.
I do think the shiny pan thing would work...but one flaw would be getting a coon to "push" on the pan vs. pulling on the pan. A trap set flat below the water surface...you would think a coon's natural reaction would be to pick something of interest up or lift on it vs. putting their weight down on that pan to fire the trap. They definitely wouldn't have a lot of weight committed to the trap pan so if the pan tension was too high you'ld probably just find a flipped trap. I think you would have better luck with a bedded trap near a shiny object...that way a coon is focused on the object and putting their foot into your trap and committing their weight to the pan wouldn't be a issue with this type of set.
Jim-NE