New here but let me say when I read this thread I was like HUH?!
Let me reverse the question asked:
Is it ethical to keep snakes stressed out in a glass "show" tank?
That would make much more sense! Rack systems are designed to hide a snake and keep their temps and humidity as close as possible to their normal habitat.
Tanks on the other hand are possibly THE most stressful environments a snake can live in. The are constantly "on display" and being watched, they stress everytime someone walks by and THATS why they spend 90% of their time in those 2 small hides you NEED to provide.
A rack system on the other hand eliminates the stress of being on display gives then the proper temp and humidity (a good cage will as well but racks imo do it better) and will be dark and enclosed (just the way they like it)!
Remember Ball Pythons are one of the most bashful, shy snakes in the Python family they are by no means curious as to what's outside nor do they want to be looked at when they are curled up or hunting for prey, you snake may be accustomed to it but believe they do NOT like it.