The CBB is "with caution" - some won't pick at corals, others will. So far this one won't even touch the aptasia in my tank so I think its going to be a model citizen! It has eaten all of the random feather dusters (not a huge deal), and might be picking at the vermitid snails (which I would welcome). Totally ignoring all corals so far. If it starts picking at my fleshy LPS, I'll just move those to a different tank. The huge downside to the CBB is that they are very difficult to get feeding and can be easily stressed by other fish, and many are emaciated when you buy them so don't last very long before they starve to death. I purposely bought this fish from diver's den because they are in optimum health and are feeding well on frozen foods when shipped. Even so, this one took a full week before it would sample any frozen food I added to the tank. I've done a lot of research on these guys and decided to take the risk. I don't know how it will go long-term, but I feel like I got the healthiest specimen possible to give it a fighting chance.
For the record, I also simultaneously added a long-nose butterfly - also from diver's den and originating from Hawaii, which is a good location for healthy specimens - while long-noses will eat inverts they are not known for touching coral. The one I got arrived in very good healthy and was a beauty, eating voraciously with the first feeding. But unfortunately he ran into the glass or got his nose caught in a rock and broke his nose at the bridge, resulting in a pretty rapid death. While I would try the long-nose again I would not do so in a tank that is under 6ft - I think it just needs more horizontal room to dart about without the potential of hitting the glass.