Summing feueraxt's pictures (taxiway with no traffic) #131 and the mental imagery of hilliard's post #138 suggesting aircraft lights on the taxiway might make a difference, I think this is where the answer lies.
There has to be some reason that not one, but two experienced crew fell for this imagery. Some kind of visual psychological trap.
As I said,
*When Tower said they had 28R to themselves, you could hear the continuing hint of bewilderment in the reply.