Well actually, Buster hit the nail on the head when he talked about the nav facilities. Getting "Visual" on a field (unless it's on the end of an ILS) need a very good crosscheck from all available nav aids before action is taken. As FO on a DC-10 I had a heck of a job convincing Capt and FE that the field they had visual was actually quite a few miles south of the intended original Amman destination. Yet there was the DME still showing 40 to go.