I am an A-Lister but my CP is not so when I board I usually head for the "Love Seat" and hope no one will take it before my CP gets on. I have had many FAs remind me that I cannot save the exit row seat and if anyone wants to take it, the seat is theirs. I totally agree with this and if someone really wants the seat next to me bad enough, I will move to a different row so I can sit with my CP. I do kindly ask people if they don't mind, my CP is coming and I would like for them to sit here, but if anyone were to say they did mind, I would gladly go find another seat further back.
So in my experience, FAs have been very good about enforcing Exit Row seat saving, but not regular rows, which is fine with me. I also rarely see an exit row not be taken by through pax, BS pax, or A-List pax, so I am not sure how many EB pax are really getting these seats. Maybe you are just lucky enough to be on the EB heavy flights!!