A logical, reasonable deduction on "How does a yukkuri treat another yukkuri that has no accessory".
However, the fake ones are always rejected by the genuine ones. Like how a typical yukkuri whose accessory has been lost is despised by the other yukkuri, the disguised one is sharply despised by the real Shell Marisas. Perhaps there are some kinds of pheromones for the shelled ones.The genuine Shell Marisas are always friendly toward each other. They're willing to do rub-rub with the others very shortly after their first meeting.Frauds produce counterfeits by simply replacing the accessory, which always triggers the reflex of Normal Marisa's dependence on its hat. Thinking its hat lost, the Marisa with an accessory replaced shows depression, while the inborn Shell Marisa is high-spirited and proud of itself.
Meanwhile, being a part of the genuine Shell Marisa, the shell should possess luster comparable to a living shellfish; the lifeless shell of a fake one is dull and dark.The inborn shell should be intact and uninjured. Therefore, when one's purchasing a Shell Marisa, he must check if there're any cracks on the shell.It's even easier to counterfeit Shell Marisa: simply replace the hat of Normal Marisa with a shell accessory. Yet it's easy to distinguish it from the genuine ones too.