TSA's counsel argued that the asserted patent was obvious in view of one prior art reference that disclosed scanning trays and a second prior art reference that disclosed carts at both ends of a machine processing trays. To make this argument, they needed an expert witness to say that it would have been obvious to combine the two prior art references in the way claimed. My read of this comment is that they failed to get their expert witness on record as having that opinion before trial, and so they were prevented from effectively presenting the position at trial. This is the sort of thing that keeps patent attorneys up at night.