By level I don't mean experience or complexity so much as the amount of baseline knowledge needed to take part in a conversation. To use your example, the old hands are fully capable of being part of a discussion on the technicalities of a case with the student, they just realize there's more to it than the technicalities. The conversation is at a lower level because the barrier for entry in experience is lower. Recognizing who someone is from the conversation they're taking part in though is much harder. A historian or police officer could just as well understand that legal cases don't depend as much on technicalities as people think and be capable of taking part in such a conversation without others in that conversation being able to tell the difference between them and a professional lawyer. The best bet then for most parties is to by default treat all others as equals of unknown origin until shown otherwise.