What crazy horse is referencing is the testimony of the defense experts, who said that the ride wouldn't run without the jumper. That testimony contradicted the testimony of many other people, including the ride operators who said that earlier in the ride's life, it would refuse to start because of a problem with a restraint, but that once the restraint was put into place, the ride would operate. If the jumper was there, that wouldn't happen -- it would have just run. Therefore, the jumper was not there at that time. Therefore, the ride could operate without the jumper there.
Other little notes:
- No state inspection in Tennessee, so not noticed by a state inspector.
- Yes, actually, Martin not noticing it could be sufficient to support a charge for reckless homicide, and in fact that may well have been the conclusion (in connection with the notice a year earlier that there were problems with that system).