This isn't ethics, except that you need as a litigator to be ready for the continuing disagreement at the Federal Circuit over how to address 103 in the context of litigation. Judge Prost, and others, are advocating the view that the same analysis that applies in prosecution applies in litigation: if the accused infringer shows a "prima facie case" of obviousness, the burden of production — not persuasion — shifts to the patentee to come forward with objective evidence of non-obviousness, or what judges who don't like patents call "secondary considerations." Today's split decision is here.
To me, this approach — "well, it would have been obvious, if you just look at the art, to make this" — inherently uses hindsight, becuase "to make this" is part of the equation. This could matter a lot in summary judgment or, here, bench trials…