the Unbreakable Vow

[geebsy]

No: HPFGUIDX 135219

 Dragonetti wrote: > 
> Remember the last term of the Unbreakable Vow, should
> Draco seems to fail, will you complete the mission.
> Well Draco certainly seemed to fail the mission,
> therefore Snape had to kill Draco. 


The unbreakable vow seems to be pretty hazy as it is presented in 
HBP, almost a catch-22  Is there a time limit magically imposed on 
it by the very act of taking the vow itself?  How does the "vow" 
know if you have completed your job?  If you take the vow as Snape 
did and become bound by it, what are your working perameters ?  How 
does the vow know if you have upheld your end of the bargain?  If 
your vow was to "Kill" someone and you failed, do you get a second 
chance?  What if you just wait until they are very old and they die 
of natural causes, or what if they fall off a broomstick and die 
accidently?    
Just asking :)

Roxane