I have to admit so many fans leaving early, irrespective of the score, is more of a concern than atmosphere. And it never fails to amaze me that all the usual reasons/excuses disappear if the PL trophy is being presented after the game.
I know it's none of my business, and the transport links are crap, but why are people leaving before 80 minutes with a minimum of five minutes stoppage time for most games? And what must the players think?
I've been to plenty of away games where home fans leave early, but it's never in the same numbers as at the Etihad and it tends to mainly happen when we're a couple of goals ahead with no way back for the home side.