I thought that after the Lauda Air 767 crash which was determined to be Boeing's fault they had to instal an interlock that prevented reverse thrust until the plane was on the ground. Boeing had proven to the FAA that flying low and slow the plane could be controlled if one engine reverser deployed, but the Lauda Air deployed at high altitude and unexpectedly so a couple hundred souls on board died. But I guess in the time span since they could have made the alteration that allows reverse near ground level. Seems like companies always need bad news to convince them that an almost impossible occurrence happens, and really hurts when it does.