Det verkar som om de är giltiga i försök, som vanligtvis inte används.
“Yes, but it took a great deal of skilled Legilimency to coax it out of him,” said Dumbledore, “and why should anybody delve further into Morfin’s mind when he had already confessed to the crime? However, I was able to secure a visit to Morfin in the last weeks of his life, by which time I was attempting to discover as much as I could about Voldemort’s past. I extracted this memory with difficulty. When I saw what it contained, I attempted to use it to secure Morfin’s release from Azkaban. Before the Ministry reached their decision, however, Morfin had died.”
(Harry Potter and the Half-Blood Prince - Chapter 17)