Evil Hermione, and Traitor Marietta

[pippin_999]

No: HPFGUIDX 155029

Lanval:
> True, only Harry passed out, like on the train (though others felt 
> the Dementors keenly. Chances are Marietta did). But I thought the 
> sudden "eerie silence" that Harry noticed on the field was caused by 
> the Dementors. A hundred of them must have had quite an effect on 
> the spectators as well, not just on Harry.
> 
> The Dementors were outside Hogwarts to catch Sirius Black, and catch 
> Sirius Black only. And here they are, a hundred of them, invading 
> the field, attacking students.

Pippin:
Actually, Sirius was there. Harry saw Padfoot at the top of the stands
just before they arrived. 

It's hard to tell which  dementor effects are felt by everybody and 
which only affect  Harry's sensorium. Lupin has
to put the lamps back on when Harry's attacked by the boggart
dementor, but OTOH, surely everybody in Little Whinging didn't
see the stars go out. We don't know whether anybody but Harry
heard an eerie silence. Diggory was able to go on and catch the
snitch, at least. 

 Anyway the dementors go back to their places and don't attack again 
(as far as Marietta knows) so why should she think she's in danger 
from them two years later? Harry of course, doesn't bother to repeat
Lupin's explanations about why dementors are so dreadful, nor does
he explain to anyone outside the Trio what they do to him, 
nor does he tell the DA that Dumbledore suspects they are going to 
defect en masse to Voldemort. 

Dumbledore begged the students not to give the dementors a reason
to harm them, so Marietta knows he doesn't think they'd harm students
without a reason. As far as we know, he didn't change that warning
after they showed up at the Quidditch pitch, nor did he insist that
they be removed.  At Harry's hearing, he doesn't seem to find rogue
dementors credible either.  In fact no one does, which would indicate
that they're quite rare.

I am not defending the dementors nor the ministry's use of them, 
only pointing out that Marietta hasn't been given the reasons that
Harry or the reader have to mistrust them. As far as Marietta knows,
they are loyal to the ministry, they are guarding criminals in Azkaban,
so what would be Harry's motive for teaching a spell to drive them away?

Up to then, Marietta could tell herself that they hadn't learned 
anything in the DA that was anti-Ministry, whatever Harry told the
Quibbler. But with the class learning that spell, it would be very hard for
Marietta to pretend to herself that she was just studying DADA 
and wasn't taking sides in the Harry vs Ministry conflict. 

Pippin