@Niemand
whether he killed them or not he is not a fraud, he is paid for the resources, the resources are there.
goblin's ear is there only to prove that it is he who kill it, but it is possible to buy them from another adventurer and to rise in rank and nothing forbids it
a rich person could very well buy resources and give them to the guild to have a better rank and yet it is not forbidden
you call it fraud, yet even in our world it's totally legal to buy the work of others for its own benefit, it's the basis of our economics