How is that crazy? They are a typical aviary bird. Just because they have long legs and a long neck doesn't mean they do the same thing as flamingos or cranes. I don't think I've ever seen them outside of an aviary, and every time I have seen them they're usually perched on something high that they, you know, flew to. The pool of potential habitat birds isn't as large as this community likes to imagine. It pretty much boils down to 'birds that walk a lot' (ratites, pheasants, flamingos, cranes) and 'birds that swim a lot' (penguins, anseriformes). There is a reason we haven't yet received any 'birds that fly a lot' (parrots, raptors, pigeons, and yes, even ibises).
IMO the ibis is a conceivable habitat animal but it's right on the line.