I will personally ask a wildlife and forestry official from Africa tomorrow for his opinion on this matter. Someone who actually deals with the bush on a regular basis.

Ball pythons are obviously fully capable of climbing, but I firmly believe it would due to dire circumstances. Which is certainly avoidable in captivity. If you believe your perched ball pythons are because they want to show you how pretty they are, or to watch stuff outside their tank, I'm just stating I disagree and believe it's husbandry related. The thousands and thousands found in the wild aren't found nesting in a tree or climbing for that matter.