Apparently no one read the cites report? 75 Royals were collected and one in a tree. There is more detailed observation of it systematically poking in each and every hole in the tree the observation period was 30 mins if memory serves. The Italian group (L, Luiselli) remarked that perhaps in regards to sub adult the classification is incorrect and semi arboreal is appropriate. It is available in journals if one bothers to read them.
That said the fact any breeder states they know about the behaviour of wild royals because they keep 10000 or 10000000 in plastic tubs is offensive. there is very little field studies done and little knowledge of what the real behaviour actually is.
There can be no absolutes. The fact still remains however that the behaviour of a royal in an enclosure bears little to no relation to a wild population. The fast wild snakes climb is hard to argue if you have read the studies (and where do snakes get fledglings of tree dwelling birds from if not from trees?) The fact a young snake is climbing can be an exploration or seeking correct temps. The nature of the activity comes into play. Calm tongue flicking curiosity is likely just that. Fast jerky not so much tongue flicks is likely some sort of stress.
No blanket statements they simply do not fit every animal. I have a big male whom often perches at the top of his enclosure he rarely skips a meal and is a healthy animal who is just curious by nature. (he gets into everything when handled) My other male if he were climbing I would be freaking out. It is not his nature at all.
Personally I don't believe tall enclosures are a good idea anything over 18 inches is hard to maintain correct temps and humidity. Personally I would say 16-18 is ideal heights.
http://ec.europa.eu/environment/cite...thon_ghana.pdf