Back to the original question - I think a lot of the "rules" that are cited to people are aimed at newcomers to the hobby, and not those that have some experience with keeping and maintaining salt water creatures. We've all seen the guy who walks into a pet store, sees a "Nemo" and a "Dory" and then walks out 30 minutes later with a 10 gallon tank and a HOB filter and these fish. The always used excuse - "Oh, I'll upgrade soon" is old hack, and its been shown that most people dont stay in this hobby for more than a year. Its becomes so common that you just roll your eyes when hearing it again. In the end, if the fish are well cared for and then moved on to a different (assumed bigger) home, then there's no issue. Would I recommend it to the newest person to the hobby - Never. Perspective is always important