Passenger with any sense will indeed take their hand/carry on bags if this is at all possible in the circumstances. They ain't stupid:
They know full well that loosing their personal documentation, passports etc in those bags is going to cause major grief and aggro.
They know loosing their expensive cameras/computer/whatevers etc will start an endless round of argy-bargy with insurance companies. All of whom will try and delay/deny payment - particularly when it's returned "damaged" or mysteriously "lost" and exactly when it was damaged/lost becomes an issue. Then the insurance companies will start demanding purchase receipts for said items...........
Yup, I'd take my stuff as well
And therein lies the root of that particular problem - utter selfishness and greed.