Pergunta antiga (os perigos da barra "relacionada"), mas achei que havia uma boa citação que vale a pena acrescentar, de onde a ajuda é dada em Hogwarts sem que o chapéu de classificação esteja presente.
(Contexto, Padfoot acaba de arrastar Ron para dentro do túnel atrás do Salgueiro Lutador)
'If that dog can get in, we can,' Harry panted, darting here and there, trying to find a way through the vicious, swishing branches, but he couldn't get an inch nearer to the tree-roots without being in range of the tree's blows.
'Oh, help, help,' Hermione whispered frantically, dancing uncertainly on the spot, 'please ...'
Crookshanks darted forwards. He slithered between the battering branches like a snake and placed his front paws upon a knot on the trunk.
Abruptly, as though the tree had been turned to marble, it stopped moving. Not a leaf twitched or shook.
'Crookshanks!' Hermione whispered uncertainly. She now grasped Harry's arm painfully hard. 'How did he know -?'
Harry Potter and the Prisoner of Azkaban - p.246-7 - Bloomsbury - Chapter 17, Cat, Rat and Dog
Agora eu não sei se você contaria isso como Hogwarts dando ajuda, claramente o seu Crookshanks que faz a ajuda, mas eu sempre interpretei isso como sendo parte da magia de Hogwarts.