Some cases and convictions are 100% right and safe. At what point do we say yes they done it because there is video evidence in every room, 10 whitenesses, they admitted it etc etc…. Do we still say ‘It might be wrong?’ Come on now!!
Given the rapid pace of change in all things digital, I wouldn't rule out the possibility of video evidence being manipulated in the future (if it's not already possible) and witnesses can be bribed or mistaken or deliberately misled. We know that people make confessions that aren't true and that murder convictions have been set aside as a result.
The Guildford Four, Birmingham Six, Maguire Seven, Tottenham Three, M25 Three, Bridgewater Four ... were all convicted, beyond reasonable doubt, on the basis of evidence that was considered infallible at the time but which was found to be flawed years and years later. And that's just the cases that became causes celebres, there may well have been others that are less high profile.
We can't see the future, and science advances at a rapid pace. We have no way of knowing if what is considered rock solid proof now will turn out to be anything but at some point in the future.
We also know that people make false confessions, so even if they admit it I wouldn't be happy for them to be executed.