Två anledningar hoppas att tänka.
Första gången trycket. Strax efter att Harry vaknar upp säger han att de kommer att utföra The Kiss "any moment now". Inte mycket tid för att övertyga de vuxna (mot Snape och utan Lupin, som inte är wolfy) för att hålla tillbaka.
"Ah, you're awake!" she said briskly. She placed the chocolate on Harry's bedside table and began breaking it apart with a small hammer.
"How's Ron?" said Harry and Hermione together.
"He'll live, said Madam Pomfrey grimly. "As for you two you'll be staying here until I'm satisfied you're Potter, what do you think you're doing?"
Harry was sitting up, putting his glasses back on, and picking up his wand.
"I need to see the headmaster," he said.
"Potter," said Madam Pomfrey soothingly, "it's all right. They've got Black. He's locked away upstairs. The dementors will be performing the kiss any moment now "
Andra - minnen kan ändras bra. Dumbledore konstaterar att Slughorn - som en trollkarl som han är - utförde modifieringen på sig själv oaktigt.
"Because, I think, he is ashamed of what he remembers," said Dumbledore. "He has tried to rework the memory to show himself in a better light, obliterating those parts which he does not wish me to see. It is, as you will have noticed, very crudely done, and that is all to the good, for it shows that the true memory is still there beneath the alterations.
Förmodligen är vissa förfalskningar (nästan) omöjliga att upptäcka, vilket framgår av det faktum att Tom övertygar Morfin att han dödade gåtorna.
"We have no memories to show us this, but I think we can be fairly sure what happened. Voldemort Stupefied his uncle, took his wand, and proceeded across the valley to 'the big house over the way.' There he murdered the Muggle man who had abandoned his witch mother, and, for good measure, his Muggle grandparents, thus obliterating the last of the unworthy Riddle line and revenging himself upon the father who never wanted him. Then he returned to the Gaunt hovel, performed the complex bit of magic that would implant a false memory in his uncle's mind, laid Morfin's wand beside its unconscious owner, pocketed the ancient ring he wore, and departed."
"And Morfin never realized he hadn't done it?
"Never," said Dumbledore. "He gave, as I say, a full and boastful confession."