Snape's Messenger Patronus ((was Re: Snape's Dementor lesson

[potioncat]

No: HPFGUIDX 182650

Pippin: 
> I am curious about why Snape thought it was  important for Sirius 
to stay
> behind, given that the update for Dumbledore could have been left 
with a 
> portrait or  a patronus.  But my guess is that Snape thought the 
message 
> would be in safer hands if it was entrusted to a human rather than 
to a 
> magical  servant. If so, he was quite right.

Potioncat:
I think he wanted to keep Black out of the fray. The last thing they 
needed was for LV to capture him. 

Just my two cents, but I also think the Order was expecting DD, not 
that Snape was the only one who knew DD was coming. That doesn't mean 
that Snape and DD didn't have some other way of communicating before. 
And Phinneas's portrait is a good possibility. Phinneas can leave 
DD's office to go to other paintings in the castle. Snape wouldn't 
have had to sneak into the Headmaster's office.

Which reminds me now, how much we discussed what DD would have been 
willing to do to Kreacher to make him talk. After what we learned in 
DH, I'd say he'd be be williing to do a great deal.