Nature of the Vow:

[Wink45zes at aol.com]

No: HPFGUIDX 145455

Wink 45 wrote:
> what if this spell means not so much that it is absolutely 
> impossible to break the vow, but that it cannot be broken 
> without the other person involved knowing that it was broken? 
> (and perhaps also the person who set the spell?) 

Wink45:
Okay, I'm replying to myself, but I did say I was going to do 
more thinking. 
. . .

We have already seen an Unbreakable Vow broken, and the results.  
Hermione set one on the list of the students who signed up to be 
part of 'Dumbledore's Army.' (Hmm, what does it say about her 
that she didn't tell everyone what she had done?).  Marietta, 
who broke that vow ("not to tell Umbridge or anyone else") broke 
out with "SNEAK" across her face in some sort of permanent dots.  
Any guesses what Bellatrix would choose to have Snape's face 
tattooed with?  I think it would be something that would make it 
very difficult for him to remain at Hogwarts, and which the Death 
Eaters there on the tower would recognize as meaning that Snape 
has broken his vow to do Draco's mission if Draco failed.  They 
do seem to know that Draco was vowed to kill Dumbledore, and 
seeing Draco fail they turned to Snape for direction. Snape had 
no choice . . . it was either kill Dumbledore, fulfilling his vow 
or have his face tattooed with "whatever?" at which time the 
Death Eaters would immediately turn on him and then kill the 
weakened Dumbledore and perhaps Draco as well.

Wink45