I've been rereading the HP books and something keeps bugging me. In Chamber of Secrets the Ministry assumes Harry used magic, because he was the only magical being around, so basically that was their explanation. They couldn't actually trace the spell to him and not Dobby.
So I was wondering what if Ron or Ginny or the twins used magic at home? Could they have been traced because they are underaged or would the Ministry just assume that Mr or Mrs Weasley used magic instead?
Sorry if anyone else asked the same thing, but honestly, I couldn't find an answer.