I just link traded with a random person and I realized, after they traded a shiny Pokemon with me, I saw the same shiny Pokemon with the same level still in their pc box! I'm worried this person may have some how been cheating, but before I make assumptions, I would like to know if it is possible to have this happen. (Just to clarify, I saw at least 4 other duplicates in his trading window and possibly more.) Thank you in advance for the help!