Seems that one would only be concerned about "carry on bag Nazis" if one were intending to ignore the carry on restrictions. If you're abiding by the restrictions anyway, enforcing carry on baggage limits would be a significant improvement in quality service. It would eliminate having to wander the entire length of the airplane looking for a crevice to stow your carry on when a tight connection has you boarding last. It would do away with discovering at your destination that while you weren't looking someone moved your small carry on a number of rows back to make room for somone's oversized carry on. It would eliminate having the cabin crew trying to coerce you to put your (only) bag in your foot-space to make room for someone else's luggage (No, I'm not giving up my leg-room so that others can carry on twice the limit)