Yes it is quite true that a high rank member may not have knowledge of what a low rank member do have about bitcoin.There are members who join bitcoin talk when they already have knowledge about bitcoin which they may have more information about bitcoin compared to some high rank member despite the fact that they are new to the forum.so ones rank can't be equate to his level of knowledge in bitcoin there are low rank members that are well knowledgeable and as such if any high rank members should make any mistakes, the low rank members is free to correct and Moreover nobody is above making mistakes.