I dont have a problem with people wanting to own such fish(be it exceptionally large or endangered etc.), but you should have to go through a rigorous licensing and testing procedure in order to legally own one. This will then weed out those that are serious about keeping the fish and are prepared to supply the room and resources to keep it, and those that just want one!
People that are serious will be prepared to go through the process and wont have a problem with it, those that arent wont be bothered.
People that are serious will be prepared to go through the process and wont have a problem with it, those that arent wont be bothered.