I'm going to preface this by saying that I'm not trying to pick a fight - just trying to understand the advice you gave the OP.
You listed 6 reasons to not co-habitate snakes. When I asked you about why candoia somehow fall outside those rules but balls don't you gave me a very cogent and thorough response.
But.......
Candoia are known better for cannibalism - more in young animals - than balls. While they are not as cannibalistic as some, the risk exists and I could probably argue it is higher than with balls.
As for your comments about quarantine and proliferation of disease in cohabitation - what is good for the goose (candoia) is good for the gander (balls). Why should a properly quarantined and tested pair of balls be any more likely to suffer from the spread of pathogens than similarly treated candoia?
Same with the concept of "cuddling" - it happens in just about all cohabited snakes - even when you provide them several optimum thermoregulation spots and a ton of space.
People have been cohabitating balls for years. Is it the optimum set-up? No. Can it be done? Yes. Should people new to snakes practice it? Probably not.........
But the same exact argument can be made for candoia. Candoia are known streaky eaters and are also known to stress fairly easily. Imports also come in parasite ridden and need to be aggressively treated.
So I'm at a loss. I can see why you wouldn't recommend cohabitating snakes in general to someone new to the hobby - I just am having a hard time seeing your apples to oranges comparison between candoia and balls.