How did Black get into Hogwarts in PoA? (Was: Dumbledore on the Dursleys . .

[pippin_999]

No: HPFGUIDX 151754

> 
> Carol responds:
> Yes, I mentioned somewhere in my mostly snipped post that both Sanpe
> and Dumbledore mention protective spells on Hogwarts even before the
> extra precautions taken in HBP, but I don't recall any mention of them
> in PoA, only the Dementors guarding the *gates* as opposed to the
> doors (which are heavy oak doors that would be hard for a dog to open,
> but unless DD is lying, he doesn't know at this point that Black is an
> Animagus). And clearly those spells didn't keep Black out, nor did the
> ghost/portrait network report him when he climbed the stairs to the
> tower. And once he had actually gotten into the school, DD knew he was
> on the grounds. Why not take additional precautions then? At *least*
> have Mrs. Norris (who can get out of the way of a wizard quite
> quickly) keep watch on the doors at night. Or a Sneakoscope that would
> go off if unauthorized people entered?
> 
<snip>> 
> And everyone also thinks that it was okay for Lupin to keep the
> Marauders' Map because he "knew" that Black wasn't getting in that
> way? (Black's actual state of guilt or innocence isn't relevant here;
> Lupin thought he was a murderer. If there was a way for Black to get
> into the castle other than the front doors and Lupin alone knew about
> it, shouldn't Lupin have revealed that information to DD?)
> 

Pippin:
Gosh, I've been pointing the finger at Lupin for keeping the map for
ages, *of course* he should have turned it in. I don't think you have to
be an ESE!Lupin theorist to admit that. As to your larger point, our
situation is analogous to Dumbledore's: it's difficult to say what
should have been done to beef up the castle's defenses 'cause we
don't know how they were being penetrated. 

Mrs. Norris is only a cat. All she can do is whisk off to tell Filch that 
students are where they're not supposed to be. A Death Eater would have
no qualms about  killing her and we know that the killing curse
can be performed without a wand. Muggles and wizards were warned
to regard Black as lethal. Fudge says that nobody but trained hit
wizards would stand a chance against Black if he was cornered --
and you think Dumbledore should have set Mrs. Norris to guard
the doors? Do you not like her or something? :)

Sneakoscopes aren't foolproof -- a Death Eater would know how
to disable or avoid them, as Fake!Moody demonstrated.

Lupin says that no Hogwarts students ever found out more about the
grounds or the village than the Marauders did. I think he *knew* that 
there was a way that an animagus could get into the castle undetected; 
that's why he felt so guilty. Lupin might not ever have wanted to
know exactly what it was -- he wasn't an animagus himself so he
couldn't have used it. Maybe they found a long lost pet door? 

There are also four open passages into Hogsmeade that Harry has 
never investigated because the Twins told him they are known to Filch. 
Those might not need wands and they might be easier to get into on 
the Hogsmeade side than the Honeyduke's passage. 

I speculate:

 Sirius could have used one of the four passages to get into the 
castle the first time. Maybe he didn't know that Filch had found
out about them, and he got lucky, or maybe he chose Halloween
because he knew that Filch and most everyone else would be
in the Great Hall. When he was thwarted at Gryffindor Tower,
he immediately left the castle through a hypothetical
animagus portal, remained on the grounds (probably *not* in
the Shrieking Shack which did not show signs of recent use)
and entered the castle through the animagus portal again when
Crookshanks brought him the passwords.

I doubt Dumbledore and Sirius had time to discuss
all this before Sirius escaped, and it certainly isn't the sort of 
thing you'd want to put in an owl. But once Sirius had returned,
Dumbledore might have had a little talk with him and
learned more about the gaps in the castle's defenses than even
Lupin could have told him. Thus he was able to provide increased
security in HBP. But as any chess player knows, strengthening
your defenses in one place usually means leaving them weaker
somewhere else.  A blind effort might actually have
helped Black.

Pippin
who always thought the extra secret passages were there just
to have a nice magical seven, and is happy to have found a use
for them. And who hopes Carol is feeling less lonely now