I didn't mean to bash rebreather instructors. I just meant that the diving experience required to purchase and train on a unit is pretty minimal. We have people with really limited recreational diving experience moving to rebreathers in the PNW. I have seen people in open water, and people in caves, whose buoyancy control and trim were poor and who were causing a great deal of silting. I know rebreathers require relearning buoyancy control, so the open water people I've seen may have been novices and learning, and we all have to do that. But not the ones in the caves.