Here is a story about the 200th person to be set free from prison and exonerated by DNA evidence. Often we pay lip service to the idea of presumption of innocence, but deep down believe anyone charged with a crime, or even suspected of one, to be guilty. See the comment to this prior post.
This 200th person proven to not have committed the crime of which he was convicted reaffirms that we must safeguard this basic tenet of law: innocence until proven guilty. This is because he shows that even when we take every procedural precaution against false convictions, they still happen. To minimize this tragedy, we must remain vigilant to the concepts set forth in the Constitution. His exoneration drives home the point even further because if it can happen to some guy who was sitting home alone watching TV, it can happen to me. Worse yet, the real guilty party went free.
While the Constitution provides this express protection in the arena of criminal law, it should be carried into other areas as well. While the burden of proof is not so high in civil matters, we must still start with the expectation that the party pursuing a claim must prove their case. For example, in dependency, neglect, and abuse court, the desire to err on the side of caution lies in tension with presuming innocence. Here, where competing interests cut the finest of lines, the vigilance must all the greater.