Is it not simple? Tell the passengers they'll be able to get their bags back during an emergency. Don't just say "leave your bags" - say "leave your bags, you'll get them back later". After drilling into passengers nonstop to never leave their bags unattended is it any surprise passengers don't leave their bags unattended? No, it isn't.
Lives are at stake; it doesn't matter if you get your bags back and that isn't hard to understand. Also, if the plane is on fire, you're probably not getting them back.
> After drilling into passengers nonstop to never leave their bags unattended is it any surprise passengers don't leave their bags unattended?
That's while going to your flight in an airport. I don't think anyone confuses the situations.