The op has used slightly arboreal. But I see your point, it appears we are on the same page of sorts the real misuse is terrestrial. They are a terrestrial species but as demonstrated by 1000s of photos they often seek higher observation ground (periscoping)

I have a pet theory that adults as they can gain a higher vantage do not feel the need to seek out small platforms that the sub adults do. That may account for the drive to gain elevation, my thought anyway.

I think that the general consensus, and certainly what I defined in my mind. Is that a climb in terms of a captive snake is a branch that allows to reach a elevation to near the top of the enclosure.