From the announcement:
There are significant differences between a “Stand Your Ground” hearing and a trial. In a “Stand Your Ground” hearing, there is no jury; the decision is made by the judge alone. In a criminal trial, the prosecution must prove the defendant’s guilt beyond a reasonable doubt, but in a “Stand Your Ground” hearing, the burden is on the defense to prove that the evidence fits the conditions of the “Stand Your Ground” law. If the Court rules in favor of the defendant in a “Stand Your Ground” hearing, not only are criminal charges dismissed, the defendant is also immune from civil actions related to the shooting. The primary focus of a “Stand Your Ground” hearing is whether George Zimmerman reasonably believed that his use of his weapon was necessary to prevent great bodily harm to himself at the hands of Trayvon Martin.
SHADES OF GREY: Interestingly, since the burden of proof is different here and in a trial, the same facts that lead to an unfavorable ruling (for the defense) in the hearing could result in acquital at trial. Basically, the situation, rather than being black or white, could be grey enough to go to trial but not grey enough to convict.