Whenever someone calls me “Rabbi,” I make it a point to object. Giving the honorific to those who don’t have the title cheapens it for those who have put in the hard work to earn it.
That being said, however, I can understand how some people, acting ex-officio, should be called “Rabbi” in the context of doing their duties, even if they don’t have semicha. The prime example that I can think of is a classroom rebbi, who should be called “Rabbi [fill in name]” by students, parents and colleagues with regard to his duties whether or not he has semicha.
The Wolf