One of our biggest concerns is the increase in instances in which you will have unstaffed exits on planes. One of the things that did not make it into the regulations was the requirement to have all doors staffed. Many studies by aviation investigation branches and government commissions over the years have cited the fact that passengers simply are not in a position mentally, and they certainly lack training, to properly assess exits in an emergency, and that this lack of situational awareness and ability to act and make life-threatening decisions in a split moment has very real consequences.
The NTSB in the United States published a study looking at approximately 40 flights in which there were crashes. They found that in no cases did flight attendants open exits when they shouldn't have opened exits, or fail to open exits when they should have opened them, whereas passengers were documented as having opened exits when there was a fire outside and smoke, which impeded evacuations.
This is one of our primary concerns with the ratios, that when you are asked to open a door that used to have a flight attendant seated at it—for example, the R3 exit on an Airbus A330—you may not open that door when you need to, or you may open it when you shouldn't. Once fire gets inside that cabin, you have precious seconds left before you hit that flashpoint moment. That's what kills people, the gases that are generated during the flashpoint. That's why we have a 90-second evacuation time as an industry-wide standard.