Ok . . .*prepares for the discussion*
I agree in the point that Snape is innocent but I think I can post things to follow up your theory.
BIGGEST SPOILER EVER!Evidence 1:
My theory begins with the missing sentence from the Bloomsbury editions:
"He cannot kill you if you're already dead"
This sentence is part of Dumbledore's dialogue when he's convinving Draco to come to the right side.
Evidence 2:
There's an article based on valid theories of why Snape is not guilty . . .
-->>Shocking news from the first ever UK conference of adult HP fans, Accio 2005, has just come in! Snape is innocent! The conference, which holds panels, presentations, games, and informal discussions, included a trial to determine whether or not Severus Snape is guilty of four charges: 1) the murder of one "beloved character"; 2) treason on account of becoming a Death Eater; 3) that his treason has continued, as he remains a member of the Death Eaters; and 4) assault and battery against minors. The Accio Grand Jury consisted of Accio delegates, and the "trial" was held on Friday, July 29th at Reading University in Reading, UK.
The event allowed HP fans from all over to send in questions and concerns via email in defence of Professor Snape, or to support the case against him. In a letter sent to The Leaky Cauldron, two of the trial's organizers express their thoughts on the decision:
It is a failing of our justice systems across the world when, the man with the smoking wand, is allowed to walk free, and claim innocence. Especially, when previously the wizarding community have, on no evidence what so ever consigned other wizards such as the late Sirius Black to years in prison.<<--
This an re-reading HBP leaved me to the conclusion that when Snape came to "kill" Dumbledore, dumbledore wan't begging to Snape for don't being killed, DD wanted indded to be killed . . . as part of the plan . . .
Theory
I've read several times the last 4 chapters of HBP and realized that there are too many reasons of why this was planed . . .
Reason #1:
When Dumbledore and Harry are entering Hogwarts in the brooms they're taking off every single spell that protects Hogwarts from apparition . . .later the HBP disaparates in Hogwarts bounds . . .When Snape shout the spell, Dumbledore may have used some wand-less magic or whatever to float in the middle of the room, but he never felt from the Astronomy room, he apparated down and later he did as he was dead on the grown . . . he disapparated later in his tomb, when we see "white flames" it was just a trick to have the dissaparition really hidden.
Reason #2:
The fact that we realized that someone could act as dead in the wizarding world withouth anyone noticing was shoking, was DD revealing his plan to Draco? . . .
Obviously he knew Draco wasn't under his "orders" that was why he tried to convince him, but he didn't use anything to convince Snape . . . that's a well hidden plan . . .
Reason #3:
Dumbledore was one of the greatest wizards of all time, he was a great Occlumens so he could easily read what Snape was thinking anytime . . .just as he did with Tom Riddle when he wanted to take a job at Hogwarts . . .DD obviously had several reasons to trust Snape . . . and it's very difficult that someone could trespass sucha great security as DD's mind . . .also when DD dies he floates . . .but when Moody used to Avada Kedavra on the spider, I don't remember it shooting into the air..
Reason #4:
How are we sure that Snape's not dead? If my theory is true he may be dead because of breaking the Unbreakable Vow . . .or Voldy's request was not to kill DD, but to use Avada Kedabra against him . .. if that's the case there would be plenty of opportunities to make a plan in which Voldy's request is accomplished, but withouth killing DD.
Reason #5:
As some of you may have noticed, Jo always includes something important in the series that is related to the Trio's lessons, like the Unforgivalbe curses, etc. In this case there was the "Whispering magic" (don't remember it's name) in which you didn't had to say the spell out loud . . .was this used by DD?
Your Theory applies(sp) here perfectly . .
Snape and Dumbledore had it all planned, and part of that plan. Snape may have prepared this potion for tha fake . . do you think this potion helps/prevents the attack of the Avada Kedavra? I think he didn't really stopped it with this potion, but he faked DD's death easily . . .DD just had to seem death . . it sould all have been a trick don't you think?
All of this was posted here:
Theory of a Great SecretWhich is a topic I did after reading HBP for the 4th time . . .