I understand all this, but are you telling me that the CC are not controlling the exits?
Additionally, why does the briefing specifically include an instruction to locate he nearest emergency exit? Doing this "fixes" its location in your mind more strongly than merely indicating its location in a schematic on the boarding card - that's because you are doing so visually and in the here and now.
What I find a little bit offensive, though, is something that is permanently evident in these discussions; the presumption of stupidity on the part of your passengers. Guess what? If I were seated such that the rear exits were nearest to me, and if in the event of an emergency the exits were unavailable for egress I would seek the nearest exit forward of me.