You're either or your guard as an ESL teacher, or you are not.
"Experienced teachers of adult English as a Second Language (ESL) know that learning about culture is part of learning English. Adult ESL learners themselves understand that language learning consists of more than the ability to understand new linguistic structures. Indeed, the coding and decoding of communicative acts requires an understanding and appreciation of the cultural context in which they occur.
Yet criticisms and words of caution by Auerbach (1993), Canagarajah (1999), Phillipson (1993), and Skutnabb-Kangas (2000) regarding the teaching of culture should not be overlooked. These scholars have criticized ELT professionals and materials alike for their hegemonic tendencies, particularly in their representations of the target culture. They claim many ESL pedagogical practices are hegemonic in that mainstream American and British cultures are portrayed as dominant and superior to the culture of the second language (L2) student. The ramifications of these criticisms go beyond simply being culturally sensitive; they can affect acquisition efficacy and ultimately the proficiency levels attained in the second language. >"
http://writing.berkeley.edu/TESL-EJ/ej33/cf.html
<<Unfortunately, teaching culture necessitates exclusionary practices that could be interpreted as hegemonic. >>
The key word there is "intepreted". Sure there are many instances when a student will interpret discussions/topics about the target culture as an imposition or hegemonic, but in my 25 years as a teacher and trainer I have seen many instances where the intentions of the academies and their teachers are indeed hegemonic. Many. I believe that approach is wrong and feel that students have the right to demand change.