Doesn't Voldemort know about Snape's loyalty?

[justcarol67]

No: HPFGUIDX 107828

Neri wrote:
As many have pointed out in the past, having DD by the end of GoF 
saying to Snape (paraphrasing from memory) "You know what I must ask
from you... if you are ready" and the pale Snape (who had just shown 
his dark mark to Fudge) saying "I am" and sweeps out, all this 
dramatic effect seems rather wasted on Lucius, or on anyone other 
than Voldy.
 
Besides, would Lucius have any relations with someone that Voldy had 
declared dead meat? I doubt it.
 
But it is very likely that Snape had Lucius putting a good word for 
him, thus bying a chance to recite his excuses before Voldy AKs him 
on the spot.

> 
> Tara responded:

I like to hope that Voldemort thinks Snape is the cowardly one and
Karkaroff is the one who is never returning.  We don't know for sure
the demeanor of these two when they were practicing death eaters...  
I think too that Snape's talents of Occulmency help him to keep his
true feelings from Voldemort.

Carol responds:
I'm just curious as to why you like to hope that. Is it because
Voldemort said that the one who has left him forever will be killed? I
 don't see how Voldemort could think it possible that anyone but
Karkaroff was the coward, since he would know Karkaroff's personality
from before and know that some of the DEs (notably Rookwood)
considered him responsible for their capture and would want revenge.
That would give Karkaroff reason to "flee." Also, it's likely that
Crouch!Moody was spying on both Snape and Karkaroff and reporting back
to Voldemort (via eagle owl?) that Snape was loyal not to Voldemort
but to Dumbledore. I don't think there's any doubt that Snape is the
one Voldemort believes will not return in the graveyard scene.

If the reason you hope Voldemort thinks Snape is the coward is that,
if so, Snape will only be punished and not killed, it may help to
consider the possibility that Voldemort has been persuaded (probably
via Lucius Malfoy, as Neri says) that Snape had a good reason for not
appearing in the graveyard: you can't apparate from Hogwarts. Also,
Voldemort is not a prophet, so "he will be killed" is not a prophecy,
even if Voldemort again suspects Snape of disloyalty after the MoM fiasco.

Carol, hoping this is helpful to Tara and hasn't bored everyone who's
heard these arguments before