I have a very large freckled (approaching 4") & it never bothers any corals. It used to not bother inverts either, but I suspect him in the disappear/death of a couple of cleaners & a peppermint. My fault for tempting him with his natural diet
Sometimes hawks will find a favourite coral, like a toadstool, & perch on it several times a day. That's about the only way mine ever irritated a coral.
Anthony