At least here in Australia U/S exits are roped off and serviceable ones are clear. I have personally witnessed, and had to fly on aircraft, where the emergency exit space has been the place to stow excess carry on baggage. I mean a suitcase larger than the person who "carried' it on, as well as the other 150 pax with their carry on. Predominant in Africa, some Middle East and common on the Sub Continent.