Just hope your not in the wrong place at the wrong time or you might end up that 1/30 where they get it wrong.
PS most of them were exonerated after DNA evidence proves they didn't do it.
PPS exoneration is not the same as pardon (we are talking exoneration in the above sources),
"Exoneration occurs when a person who has been convicted of a crime is later proved to have been innocent of that crime."
"A pardon is the forgiveness of a crime and the cancellation of the relevant penalty; it is usually granted by a head of state (such as a monarch or president) or by a competent church authority."
Don't think that confessions are a sure fire way to do it either the rate of false confession is comparable to false conviction rate (7%) source: http://www.sciencedirect.com/science/article/pii/S0191886906000432#SECX10
Or that eyewitnesses will get it right (75% of exonerations involve eyewitness misidentification) source: http://thegazette.com/tag/witness-misidentification/