That happens all the time, when people confess to a charge ahead of time, instead of proceeding to a trial. Remember that the purpose of the trial is to find out whether they are guilty when there is a factual dispute about that question. Here, I suppose the existence of a factual dispute is itself disputed: does that need to go to a jury, or is it enough that the trial judge and the appeal court looked at the record and decided there wasn't a dispute?