The way I see it, if a guy purchases a fish like that from an LFS, the person selling it to them should be a little outgoing and go ahead and ask if they can see their set-up sometime "since it must be huge to house that species of fish". Anyone who's got a tank that large should be willing to show it off. If they're reluctant, then you don't have to feel bad about being reluctant or refusing to sell it to them, since they probably don't have a big tank anyway. I think that the best way to go about this is for LFS's to require proof of their possession of a tank large enough to house these animals and proof that that animal will be going into said large tank.