As someone who has spent a lot of time defining and enforcing processes (yay), it is far easier and more understandable to adopt a hard rule for this sort of thing. You don't want people to be debating whether or not their backpack is the acceptable size to include, while someone else's laptop case is not. Then you have someone saying that they are allowed to take their backpack, but it is in the overhead bin one row behind them, so could you just pass it to me...

For life or death situations, you need to have short clear rules that are easy to follow.

Remember, you will only actually lose your stuff if the plane is destroyed. If the plane is in the middle of being destroyed, just get out and be glad you are still alive!

> it is far easier and more understandable to adopt a hard rule

Looking at this thread, we might need to put into regulation that taking baggage during an emergency evacuation is criminally negligent. (If someone behind you dies, negligent homicide.)

Agreed. This is your life at risk. This is the lives of others on the plane at risk.

Everything else takes a back seat to those priorities.

> A backpack carried on the breast would not occupy space in which another human could have stayed.

An individual backpack might not displace an individual human but across ~300 passengers those 50 backpacks will displace people.

There are multiple seats per row and only the first person of that row may benefit from the concurrency, as each person gets into the isle for that row they will add those seconds and that is sequential not concurrent. Also you likely haven't been in a trampling crowd situation, bag on a chest doesn't occupy zero space.

> The seconds are not added, because the corresponding activities are concurrent

A passenger has practically zero information as to the seriousness of the crash. It could be a doozy. Or there could be a fuel leak waiting to ignite.

> backpack carried on the breast would not occupy space in which another human could have stayed

You're claiming given two lines of people, one wearing backpacks, the other not, that the latter cannot be compressed more than the former?