I have ever duped a redosm katana +6 at cabal MMOWebs. But not with this trick. I did it when there was very lag at my computer, cuz my dad is downloading, my sister is browsing, and i playing. And the cabal is very laggy. I put the redosm in the storage then i immediately log out cuz i want to switch channel. But when i logged in, i saw the redosm still in my inventory, and there is also 1 in the storage.
Why it could be? I think u can guess....
if you want to try this, i give a warning that this doesn't always success. Often fails, but if you were lucky, ur items may be duped.