[Echognome]

I don't understand any concern about receiving incomplete information. If you ask for the opponents to explain the auction, then it is their duty to inform you fully. It is not sufficient, for example, to give the name of a convention. Once I ask the opponents, I rarely follow up. If they have failed to give proper disclosure and I was damaged, then I can call the TD later. Of course, I'm a reasonable person, so if I need a small clarification, I don't mind asking. So I find the whole dialogue that happened a bit mind boggling. First off, what's the problem if someone asks you to explain your auction. They have kindly waited to ask before the lead. It seems appropriate now to give them as much information as they want. Sometimes this is an art form as opponents may just want cursory information. But once they inquire further, then just give them everything you know. I would certainly give a warning to describer about their behavior.

Law 75C said:

Answering Questions on Partnership Agreements
When explaining the significance of partner’s call or play in reply to an
opponent’s inquiry (see Law 20), a player shall disclose all special information
conveyed to him through partnership agreement or partnership experience,
but he need not disclose inferences drawn from his general knowledge and
experience.

Now for West, I would also give a warning if not penalize. At first it wasn't clear to me whether West was truly ignorant (in which case warning) or was just bating South. But upon re-reading, West initiated the question about RKCB, meaning West was aware of what RKCB is. So it seems to me that West was being overly obtuse to make a point. I find that very unnecessary and bordering on being unethical.

[awm]

A few notes here:

When the auction ends, the declaring side should give any delayed alerts. Typically this means alerting and explaining bids above the level of 3NT which may have been artificial. One such responsibility is to indicate when an ace-asking auction has occurred; frequently when people do this they also explain the response "We've had an ace asking sequence; 4NT was keycard and 5♥ shows two without the queen" although this explanation is not strictly required without prompting. On the hand in question, there is no indication that the declaring side fulfilled this responsibility.

While it certainly makes sense to ask "please explain the auction" and this is what people are supposed to do, I've found that in many attempts to ask this question I have never received an accurate and complete answer. Most of the time people say things like "it's standard" or "it's natural" or "we play 2/1" none of which is a full explanation. I find that I virtually always need to query specific bids or ask specific questions like "does opener's high reverse here show extras?" or "was this bid necessarily a suit or just control showing?" Typically I start with "explain the auction" and then become more and more specific until opponents reveal the information I want. If I never asked the more specific questions, I would never get useful information, and would probably end up calling the director on many many hands. Director would not look favorably on this, and would probably say "if it really mattered whether this bid showed extras, why didn't you ask that?" I certainly would not be inclined to make a ruling against folks who asked for an explanation of a bid, received an incomplete explanation, and then asked for further clarification on the basis that "they didn't need the further clarification and might only have asked to confuse declarer" since this is tantamount to accusing them of cheating and declarer really should have given the complete explanation the first time.