I think the risk in leading a refresher dive is something going wrong during that dive. I logged training dives to show that nothing of health consequences happened on the dive. I can't recall an instance when something went wrong on later dives and people went after a previous instructor for a lack of competence.
IIRC, there was some question about the quality of instruction provided to both Gabe and Tina Watson when Tina drowned in Australia shortly after certification. Her husband's attempts at rescue were so very incompetent that he was accused of deliberately killing her. It was eventually determined that no, the two were just wholly incompetent divers. Gabe was a NASDS-certified Rescue Diver, and he had gotten all his training from the same instructor who certified Tina, and reports indicated that the amount of time spent on instruction in those classes was not enough to meet standards. Yet, other than people shaking their heads sadly, nothing was done, and I don't see how anything could have been done.
The people who did get in legal trouble in that case was the dive operation. They allowed the two to skip the supposedly required checkout dive because of Gabe's certification level. So it was the people involved in the dive itself who were at legal risk, not the evidently incompetent instructor.
IIRC, there was some question about the quality of instruction provided to both Gabe and Tina Watson when Tina drowned in Australia shortly after certification. Her husband's attempts at rescue were so very incompetent that he was accused of deliberately killing her. It was eventually determined that no, the two were just wholly incompetent divers. Gabe was a NASDS-certified Rescue Diver, and he had gotten all his training from the same instructor who certified Tina, and reports indicated that the amount of time spent on instruction in those classes was not enough to meet standards. Yet, other than people shaking their heads sadly, nothing was done, and I don't see how anything could have been done.
The people who did get in legal trouble in that case was the dive operation. They allowed the two to skip the supposedly required checkout dive because of Gabe's certification level. So it was the people involved in the dive itself who were at legal risk, not the evidently incompetent instructor.