The vaults at Gringotts

[sarahlegend]

No: HPFGUIDX 40193

Hey everyone!

I've been lurking around HP4GU for a while and love the great
discussions that go on here - they really help me to get even more out
of the great HP books.

Anyway, a contribution of my own to the discussions of
"foreshadowings" JKR is so good at weaving into the stories...

(UK ed. of PS p57) - "An' I've also got a letter here from Professor
Dumbledore," said Hagrid importantly, throwing out his chest.  "It's
about the You-Know_what in vault seven hundred and thirteen".

(and from the UK ed. of POA p315 - Sirius Black's note to Harry
delivered to the Hogwarts Express to explain about the Firebolt... ) 
- "I used your name but told them to take the gold from Gringott's
vault number seven hundred and eleven - my own".

So...

(1)  Why did Black bother to mention what his vault number was (unless
he was being such a kind godfather as to give Harry access to his
wealth if Harry needs it)?

(2) How come Dumbledore or Hogwarts itself has a mega-high security
vault just one door (if the Gringott's tunnels use the 'odd numbers
one side even numbers the other' system) or two doors away from that
of a convicted murderer and Azkaban prisoner?

and (3) - WHat the heck is in vault number seven hundred and twelve?

Sarah xx