Crank windows can't be electronically disabled to prevent the kids from operating them in the first place (which is also one way of solving this problem). They also can't be remotely operated by the driver to override some kid screwing around with the buttons while on the road.
Of course turning off the car and removing the key should also solve this problem. They neglect to mention that perhaps leaving a little kid ALONE IN A RUNNING CAR might be even more of a risk than some freak window accident.
When left alone, very young children frequently develop terrible, gorilla-like strength that allows them to do things they would never manage when supervised. With fans, for example, children in the throes of a gorilla-frenzy tend to pull them down, then tear the cage off the fan, wire by wire, without destroying the motor or unplugging it; the exertion leaves them utterly exhausted to the point where they fall asleep with their faces right in the blades.
Actually, I got my fingers sliced by a metal-bladed fan before. My grandma had it in her attic, and I thought it was awesome, so I took it home. I had it running, and in the middle of the night with it running, I reached out for something, and got my fingers sliced.
No real damage, life lesson learned. Get your kid a fan! And some electric windows too, I guess. Never got messed up by one of those, but it's sure to teach something or other.