Fortifications at Hogwarts

[Arya]

No: HPFGUIDX 101928

Arya wrote:  
Hmm, now you have me thinking.  Perhaps Hogwarts, to an 
intruder with evil intents, can become a maze?  With all those 
moving  staircases <snip> will effect either a maze or a trap if they 
are in a "defensive" mode?  <snip>  I'm of the belief that  Hogwarts  
has many more eyes and ears than just those that can be seen.  
------------- 
Mandy here:
Nice idea except that Sirius gained entry, all the way into the 
Gryffindor common room, with evil intent.  Everyone was wrong in 
believing he was after Harry when in fact he was after Peter, but 
either way, he was there to commit murder.  Wouldn't the school have 
wanted to confuse him to protect the innocent inside?  Perhaps the 
school recognized him as one of its own, but then it would recognize 
Voldemort as Tom, one of its own too.
----------

Perhaps it wasn't in defensive mode?  Perhaps, because Sirius would 
have used a secret password to get in through a tunnel (which I am 
sure he used) he diasabled any alarms?  Perhaps, Dumbledore the 
conveniently all-knowing of just enough to help the plot, get the 
castle out of "defensive mode" just to allow Sirius to enter?  
Perhaps, Sirius knew some tricks we've never heard about.  I've 
wondered if, when using the map and you come upon a locked door, will 
the map always give you the password?  It does for "dissendium".  
Does that map tap into some of the innate magic that is Hogwarts?  
(Perhaps one of the makers of the map had founders blood that gave 
the map this ability???)  If so, perhaps Sirius knew something else.  
Perhaps Dumbledore had the castle set to just prevent anyone from 
stealing/capturing Harry--afterall, DD at least knew Sirius, as a 
purported servant of LV, wouldn't really be after Harry to kill him 
but to capture him and attempt to bring back his long lost master.  

Just thoughts....
Arya