I do not recommend to anyone that they keep non-breeding snakes together, but I also think that people should understand that there are no "rules" so to speak. The greatest thing everyone has to their success with animals is using their own intuition. Using intuition, can take time to get right! It is not a simple yes/no, if-then-may-be answer. Could anyone ever guarantee the actions of any human???? Animals are no different, yet refreshingly more predictable/reliable.
Yup,,,,, I have housed 2 girls together since October '07.
I haven't noticed in my PERSONAL & INDIVIDUAL experience, that they have ever competed w/each other. They actually seem very relaxed and unstressed w/each other. Although, I'm sure they wouldn't necessarily "miss" eachother if separated. (ummm, actually, one does look around the tank if I take one out,,,, but that probably doesn't mean much)
They are in a 40gal breeder display tank w/branches & fake ivy that they like to climb every night. They have never been exposed to new snakes. Every time I feed them, they are taken out of their tank. I use big rubber maid containers w/lids to feed them. When they're done swallowing, I clean them off from head to tail w/ a wet towel (I AM paranoid about one smelling like a rat to the other!!!!!!) So yes, I admit that I feel the fear of other people's warnings! Why do I still keep them together???? Well, there is no GREAT reason,,, only that through time, my particular pair doesn't seem to mind the arrangement,,,,,,,,, I am planning to get them their own digs soon........... as they are both about 900grams now.
Now, remember that these two are girls, and remember that they've been together since they were 2 months of age......... Any other circumstance could be DRASTICALLY different. But for me, my 2 girls have been healthy and great at living together for the past year . I think that it's all about the circumstances.
Just my experience.