system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] How is Hermione allowed to repair Harry's Glasses outside of Hogwarts?

In The Chamber of Secrets, after Hagrid rescues Harry from Nocturne alley, they run into Hermione and she fixes his broken glasses, how does this not fall under the under age magic rule?
gpt
It's explained in the book that the Trace can only detect magic being used in the vicinity of an underage Witch or Wizard, which is why Fred and George could use magic at their house to make the things they sell, the Ministry knows someone used magic but assume it was the parents and expect the parents to discipline any underage magic use.

Likewise, Hermione is in Diagon Alley, a place filled with underage Witches and Wizards and their parents, as well as others just going about their day. Thus the ministry has no idea an underage Witch (Hermione) used magic so can't punish something like that.