Not long ago I started a KSNM party for "Copycat" with 5 other players, including a player called Gilder. We all agreed beforehand, himself included, that every drop worth more than 100k would be split between all members. During the KSNM he got the Destroyers he was after, and we got 4 Fuma Sune-Ate drops. Afterwards as each Fuma sold, he happily took his shares of each one. His Fuma drop was the last to sell, and he kept the gil for himself, refusing to respond to any tells from anyone who was at the KSNM. After attempting to contact him many times over the course of a week it became obvious that he had every intent of stealing not only the gil from his drop but also equal shares of the gil from every other drop.
It's not a substantial amount of gil that he stole, but I want to make it known that this player cannot be trusted.