There is an exploit with duels currently where two people can enter a duel room and cause one of them to enter duels even though they don't have the tc. If they win I believe they are awarded the tc but if they lose nothing is lost. It requires the player to have already duelled with the correct amount previously - after this they could potentially remain in duels without the tc if the second person continued to help them do so.

I'll explain the exploit to an admin in private messages to avoid people using it who don't already know about it