My opinion is the following. Almost all young ball pythons will climb. Some smaller males will continue to climb into adulthood.
I base this on two things. My own personal observations of my not small collection, and the following study http://www.tandfonline.com/doi/pdf/1...50009809386744
Honestly I don't care if people put climbing stuff in with their animals. My reservation with advising it is that the higher the enclosure gets, the harder it is to regulate the environment which for new keepers tends to be one of the more difficult things to do. And I will never advise putting something from outside in a cage with any animal.