Not what I am aware of, at least none of the guests spearfish the Lionfish when I was there. Only DM / guide did it. My job was only to count the Lionfish and report / point it to the DM, so he could jab the sucker and feed it to the Reef Sharks.
DM tried to teach Nassau Grouper to eat Lionfish once, but the Grouper did not like it. The Grouper had a fit, after swallowing the Lionfish, tumbling around on the sandy bottom, making a cloud of dust, then spat out the dead Lionfish, left the scene. Not even in a minute later, a Reef Shark grabbed the remnant of badly chewed up Lionfish and ran off, chased by other Reef Sharks.