Harry Potter - Underage use of magic question

When Dobby uses magic at the Dudley’s house, Harry gets a warning message from the Ministry of Magic stating that underage use of magic was forbidden. (Chamber of Secrets, I believe) Later in the series (Order of the Phoenix) when the guard come to get Harry, Tonks uses magic to pack Henry’s truck and then Mad-Eye uses a disillusionment charm on Harry…why didn’t he get in trouble for this as well? Is it different because his Aunt and Uncle were not home or some other reason?

a wizard did it

Because HE wasn’t the one doing it.

The law is against children doing magic, not having it done to or for them.

No, it’s explicitly stated in Deathly Hallows that the trace can only tell that magic happened in the house, not who performed it. Wizarding parents are expected to police their own younguns, so it’s mostly Muggleborn wizards and witches who bear the brunt of Underage Magic enforcement.

JKR just made that up because she needed to in DH

Harry didn’t do the magic in Book two either, it was Dobby so it’s not as simple as that, Chimera. I think the fanwank is that if you are of age, regardless of where you are, your magic doesn’t trip whatever sensor the Ministry of Magic has. However, in Chamber of Secrets, there were no magic using adults so the burst of magic set it off; house elf magic apparently being unregulated.

This is what I thought… which is why I’m confused about him not getting in trouble for this particular instance of magic used at his muggle home.

I don’t remember the situation from Order of the Phoenix off the top of my head, but it’s possible* that the Order had people in the right places at the suppress any action on the part of the Ministry.
*Another fanwank, yes.

Harry and Dudley were attacked by dementors. Harry produced the patronus to get rid of the them. Tonks sent the Dursley’s a letter telling them they won some best looking landscaping award to get rid of them. The guard then came to get Henry and while preparing to leave with Harry, Tonks and Mad-Eye both performed magic at his house…

the ministry knew that wizards would be picking harry up in ootp. also the ministry knew that wizards would be picking harry up in gof when arthur weasley connected the dursley’s house to the flue network. they knew that dumbledore was picking up harry in hbp. in all those cases over-aged wizards were in the location with harry.

dobby set off the trace because there were no over-aged wizards or known house elfs in harry’s house.

in dh they were careful to use non-magical means to leave the dursleys. only over-aged wizards used the potion.

It’s been quite a few years since I read that, but did they? IIRC, while Moody and Tonks are connected to the Ministry, weren’t they operating on their own behalf and not as ministry officials on OOTP? I don’t think it was ever stated or even implied in that scene one way or the other. Seems to me that that is a small plothole, or one must fanwank and assume that one of the characters submitted the proper paperwork or whatever, or magic-ed a blind spot in the underage magic whatchamadoodly detector for that scene.

I understand they prefer the phrase “mature wizards.”

kingsley and tonks were with the aurors office. they could have just put in that harry was being moved to meet the weasleys. there were quite a few owls being sent all over the place.

If you really want a contradiction, how about Harry using “lumos” to read in bed in IIRC Prisoner of Azkaban. Mr. Dursley runs upstairs but can’t catch him in the act. Not a peep from the Ministry about underage magic.

Yeah, Ms. Rowling couldn’t keep her details straight. Well, that was the movie, anyway - the book might not have had that fault. Hmmm.

Why can’t it just be that the Ministry can only detect magic being used at a certain intensity or over? The lumos spell simply isn’t enough to trip their sensors. Alternatively, it could be like speeding. You can get away with it more easily on the interstates than on a city street because there are more cops around in the latter. Moreover, all the persons doing the magic monitoring may not be of the same ability or diligence.

That was only in the movie.

My response to the OP is the same as other posters have said: in book 5, people moving him to another house are people from the Ministry of Magic, including people from the Law Enforcement Department, so it is not surprising that the “authorities” would know that it’s not Harry doing the magic.

Not to change the topic, but the biggest instance of dumbassery (is that a word?) in the Harry Potter books is Harry not using his magic mirror to contact Sirius Black in the last part of Order of the Phoenix.

And then Harry was summoned to a trial and charged with breaking the underage magic use law and nearly expelled from Hogwarts.

He didn’t know about it until after Sirius was dead. He stuffed it in the bottom of his trunk (without unwrapping it) and didn’t dig it out until the end of the semester.

He knew what it was, having read the note that accompanied it in January. But he viewed it as an easy way for him to get Sirius caught, so he set it aside, and didn’t remember it in June (until he was packing to go home)).