Recently there was long thread about the BCA. I can now post possible answers to some of the questions, such as "Why is the BCA still raising membership prices when there is a significant amount still left in its coffers?"
A solid one leaning against the side of a building, yes, but a wire one free hanging in a cave, no they wouldn't. An experienced leader of novices could tell you lots of anecdotes about novices who couldn't climb a ladder.
Actually, not only have I heard of it, but I've also used it both on the surface for practice and underground for real. I find the question somewhat patronising and totally unnecessary.