Teaching: Sharing with others with what we have learned from others along with our life experiences.
Learning: Opening ourselves up to experiencing something offered from somebody else, or a life experience.
I think that we all should be open to be able both teach and learn. Rank is not a requirement for either thing to occur. We should be open to learning from somebody with any rank (learning from positive, neutral or negative experiences) at the same time as being able to share with a person of any rank, what we have gained to date.
People get too caught up in rank, organizations, hierarchies, ..... for all of the wrong reasons. This situation usually stifles ones ability to learn from experiences.
I think this post is also what Jun had in mind when he started Aikiweb.
"The only thing a black belt represents is that you have the potential to be a good student" Shoji Nishio Shihan