while I am not in principle opposed to rack systems, I note that I often think of them as appropriate for species I have no experience with, and no desire to keep
I do think they are a great convenience for people who keep large amounts of animals, and they help to provide sanitary conditions in settings where that is needed
however - the argument that snakes don't have the urge to move unless something prompts them is just as anthropomorphic as the claim that they need branches - and perhaps not entirely accidental
according to my vet, obesity is in fact the #1 underlying cause in the majority of disorders affecting captive animals
isn't that because we expect them to live like us? (in cubicles or on a couch, with no exercise or appropriate diet, just as long as there is climate control)
we do all thrive in this setting too, don't we?
this has nothing to do with emotional states - it's basic physiology
in the wild, exercise is a built-in factor of feeding, and on a purely physiological level muscle tone is not entirely irrelevant to metabolism
and - "feelings" aside - there is a case to be made for the option to self-regulate
I don't think it kills a snake to be in a tub, and I don't know that they "miss" stimulation or exercise, and I do have one snake that might as well be housed in a tub
they do become more interesting when given the opportunity to move around; even my much more sedentary kings and hogs do more than lie around between meals