Of ignorant informants?

How does one define an 'expert' in the field? This question has been on my mind since I've got here, and is nowhere close to being answered.  So many times, my informants in the field have treated me as the expert.  Being more than well-acquainted with the core texts, concepts and debates in Islam and, more specifically, Sufism, I can hold my own in most conversations on Sufi Islam, and also answer questions posed to me about certain topics with reasonable ease and confidence.  But I still find these instances of being the expert quite disconcerting.  As an anthropologist, being positioned as the expert seems to be at odds with the idea that it is the "native interlocutor" who is the person in the know.  I'm here, or at least that's the script most ethnographers tend to follow, to learn what local informants have to teach me...even though many of my local informants feel that I know way more than them about Islam. 
This hierarchical valuation of the "little tradition" and the "great tradition" (to borrow Robert Redfield's terms from old-time Anthropology), understandably makes me uncomfortable.  Where I value what the subaltern has to say, I find that the subaltern sometimes sees little worth in its own knowledge-production.  
Where my subaltern informants are willing to speak, to tell me what they know and feel about Sufi Islam with enough self-assurance, there is also the internal hierarchy among those in the field that I must contend with--the hierarchy between the lettered folk with textual expertise in Islamic theology and Sufi schools of thought on the one hand, and those who transmit and/or adhere to folk-Sufism or Sufism for the masses (if I may use such terms) on the other.  Ask a member of the former group and they usually tell me that any time I spend talking to those of the second category is time wasted, that I will learn nothing about Sufism or Islam from them.  To them, my informants who are not well-versed in the textual dialogues of classical Islam are wholly ignorant. 
While it is true that most of these people, who are members of India's Islamic Intelligentsia (I adore accidental alliterations), could tackle the nuances of theological and philosophical debates within classical Islam with ease, they don't know jack about the ways in which ordinary people's life-ways are fundamentally altered by these larger intellectual debates; they could hardly give me even an idea of the kind of religious transformations that Sufism and the lack of it renders in the contemporary Indian setting. 
So who then is the expert? Me? My scholarly interlocutors? Or my lay informants? And who among us is ignorant? And of what?