I think that in that case it remains on the cheater's conscience, and the prize can be considered as received by that very roommate, who simply decided to remain anonymous. I think it's unlikely anyone would agree to pay someone money and deprive themselves of the pleasure of playing for a game disc they already own and respect on the forum ;)
I will repeat my question to the organizer: "Will the fact that the winner sent their save earlier have any impact on the evaluation?" I sincerely hope not :)