Pax taking hand luggage in an evacuation
Pax will always try and take hand luggage with them in an evacuation, as has been seen countless times before. In an emergency situation people react instinctively, no amount of pre-flight briefing is going to change that.
Instead of blaming the pax for acting instinctively in what is no doubt their first and only evacuation, criticism should be directed at the airlines or regulators. If you don't want pax taking their luggage in an evacuation don't let them take it into the cabin in the first place.