Actually, you have it very much back to front. In the case of EF we were encouraged to impart cultural lessons.. Something I disagree with. My job is not to teach my students about British culture, it is to teach them to speak English. If they are going to visit England, then a 1-1 class about the culture is warranted, but not as a regular part if thier language classes, no more than I would teach them cultural norms of the USA, Canada or any other English speaking country. If it is a corporate ( business) class, whose students are going to be dealing with native speakers, then yes, some aspects of British culture and etiquette is appropriate. But as I said before, unless the topic comes up (national stereotypes are a good way to teach adjective extension and articles) I would never do a lesson specifically about British culture.

Otherwise my job is to teach them how to speak, write, read and listen fluently in English. Not to be their cultural adviser. This has nothing to do with profit and everything to do with my role as a language teacher. I spent 3 hours in adult classes yesterday ranging from A3(PET) to C2(Proficiency), these people are learning English to improve their employment chances... If I were to say "OK, today I'm going to teach about life in England!" they would not be impressed! They are attending classes to learn the English language, not learn about what English people get up to at the weekend.