Is Zimmerman innocent? What about Snowden?

Under U.S. Law you are innocent until proven guilty, but in both cases neither Zimmerman or Snowden are making claims that they are innocent of the charges brought against them. Instead, some may say that they are guilty and letting the courts prove them innocent.

Check out this opinion article by Steve Rosenbaum on the topic.

What do you think? Is the legal system acting the way it should or are the courts setting guilty people up to walk free?