From "Shepherd the Flock of God", pp. 2. 89-90:
2. The chairman should invite the accused to make a personal statement. If the accused contends that he is innocent, the witnesses to the wrongdoing should be presented and their their testimony should be given in the presence of the accused. It is best that the witnesses give their testimony in person. ... The accused should be given opportunity to respond to the testimony. If he wishes to present witnesses to establish his innocence, the judicial committee should allow them to give their testimony.
3. Hear only witnesses who have relevant testimony regarding the alleged wrongdoing. ... The witnesses shoud not hear details and testimony of other witnesses. Observers should not be present for moral support. Recording devices should not be allowed. - [Emphasis in original]
Notice this little gem from the Elders' manual:
4. In the rare event that testimony presented during the hearing causes the judicial committee to conclude that the matter should not be handled judicially, the hearing should be suspended. - Shepherd the Flock, p. 90 - [Emphasis added]
Don't you love the way they describe it as a "rare event" that testimony heard during a JC would prove someone's innocence!
This pretty much proves that in most cases the decision is made BEFORE the judicial hearing even starts, the procedure is just a formality.