Okay, sticking yukkuri in this seems like a really stupid idea to me. It'd work fine without them -- it'd just collect water in that bowl.
The yukkuri are actually counter-productive, despite how it's sold -- instead of just having to empty out the water, you now need to wash out a mess of mold and melted yukkuri.
If you're in it for the abuse aspect alone rather than practicality... it also fails. It's slow-acting, and isn't much more than annoying before it becomes fatal.
Plus, I doubt the realism of moist air having that dramatic an effect on them -- if it were really this bad, they'd all die off when it rained, even if they found shelter, because the humid air would make them melt or mold. Forget just falling in water -- even going near a swamp or even just a pond on a hot day would be catastrophically fatal.
All in all? Mister Artist, the art is good, but the idea simply can't take it easy. Think of something more plausible and effective either as an actual use of yukkuri or as an abuse method.
would never maake it to the market, would be to much of a health risk