Eh, the chances of ever having this impact you are incredibly remote. And yes, the “cost” of following this guideline is low, until you consider that you could have similar rules for hundreds of other incredibly rare situations, none of which will ever happen to you. Seems exhausting for no benefit. I’ll just continue to keep my stuff in my backpack under the seat, and I can grab it if needed. Or not, and I’m sure that’ll be fine too.

Also, there’s no indication that anyone who left the plane without their ID or passport is just being left in the terminal for days, making this guideline even less valuable.