Lia: It is a warning and remove the illegal card and replace as stated above. The bigger problem is the lack of decklists. If this is a CC, being santioned by POP, wherein the W/L record counts towards the world rankings, then that is a HUGE problem. That is the reason the PTO/TO/HJ MUST use decklists and review them before the 1st match for illegal cards. If you look in the tourney section here at the Gym, there are multiple links in the threads to standard deck lists, just for CCs. They have the symbols of the legal sets in the corner. I have no idea why a HJ/PTO/TO would run a santioned CC like this w/o a decklist, much less without a deck check at least once during the tourney. In both CCs my son and I attended, it was mandatory to fill out decklists and sometime during the tourney, each PTO had the players count the cards in the deck of their opponant before that round's match. Looks like poor planning by the PTO/TO/HJ IMHO.
Keith