If I was a passenger in a car which was about to crash, and the driver began pumping the brakes, I would be forced to intervene.
Mid-crash, I'd be like "Wait just one ******* minute! What the **** are you doing?!" I'd not move an inch until I got a full explanation, and I'd then step out of the car, give the driver a sincere look of disgust, and walk away, leaving him to crash.
But in all seriousness, are there actually people out there who believe you should manually pump the brake? My fears for my own safety on the road have just increased tenfold.