system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter (films)] When Hermione, disguised as Bellatrix, tried to break into the bank, the goblin asked to see her wand as identification.

They used an Imperious spell to bypass this requirement. But, I thought that they *had* Bellatrix's wand. Didn't they show it to Ollivander and get his assessment of it earlier? Why didn't they bring it with them and show it?
gpt
Hermione Granger was, in fact, using Bellatrix Lestrange's wand, and thought it would make the disguise all the more convincing. What Hermione, Harry Potter, and Ron Weasley did not factor into their planning was that the news of Bellatrix losing her wand would be spread among the forces loyal to He-Who-Must-Not-Be-Named; You-Know-Who encouraged that kind of thing, since shaming those who had failed him was part of their punishments. The Gringott's goblins, who were answering to You-Know-Who at that time, were also aware of this.

The goblin Griphook, who is far more adept at reading goblin body language than any human could be, realized that the Gringot's goblins were aware of this, and that showing them Bellatrix Lestrange's wand would actually confirm them to be impostors.