Why not floo instead of thestral to London?

[maneelyfh]

No: HPFGUIDX 91808

--- In HPforGrownups at yahoogroups.com, "Geoff Bannister" 
<gbannister10 at a...> wrote:
> --- In HPforGrownups at yahoogroups.com, "cubfanbudwoman" 
> <susiequsie23 at s...> wrote:
> > > 
> > > My point was that he was in a flat panic, ready to do anything 
to 
> > > save Sirius and had been flapping hysterically about how to get 
> to 
> > > London for the past couple of hours. 
snip
> Geoff:
> But that doesn't occur to anyone at that point. I've just re-read 
the 
> relevant bit and who is it who keeps a cool head and comes up with 
an 
> answer at this point? 
> 
> Luna.
> 
> "'Yes,' said Harry.... 'and I'm sure Sirius is still alive but I 
> can't see how we're going to get there to help him'......
> 
> ....'Well, we'll have to fly, won't we?,' said Luna in the closest 
> thing to a matter-of-fact voice Harry had ever heard her use.
> 'OK', said Harry irritably........'..Ron's the only one with a 
> broomstick that isn't being guarded by a security troll, so -'......
> 
> .....'There are other ways of flying than with broomsticks,' said 
> Luna serenely.
> 'I s'pose we're going to ride on the back of the Kacky Snorgle or 
> whatever it is?' Ron demanded.
> 'The Crumple-Horned Snorkack can't fly' said Luna in a dignified 
> voice, 'but they can and Hagrid says they're very good for finding 
> places their riders are looking for.'
> Harry whirled round. Standing between two trees, their white eyes 
> gleaming eerily were two Thestrals....'
> 
> (OOTP "Fight and flight" from pp.670-672 UK edition)
> 
> /No one/ thought of Floo powder. The only options which crossed 
most 
> people's minds were broomsticks
snip

Isn't the floo network being monitored? I am pretty sure it says 
something to that effect in the book, and not just at Hogwarts.  
Sorry I cannnot grab my book as I am on crutches. If Harry and Mr 
Weasley could not use the floo network to go to the MOM and since 
Sirius almost got caught talking to Harry, I dont think the gang 
would even think of using it. Plus, they did not know what was going 
on at the castle...if they went back would they have been free to use 
the floo or even go to McGonagal? I dont think going back to the 
castle was an option, and here they had a means which would deliver 
them to their destination. 

I wonder if when one rides a threstral, does the rider become 
invisible, or would you see a person flying thru the air clutching 
something invisible? If not, surely someone must have seen a group of 
kids flying thru the air.....
Fran