We all know that as lawyers have an obligation to cite known adverse precedent to the court.
There are two reasons why this rule should be followed (other than the all-too-obvious point that the rule exists). First, the failure to cite adverse precedent means you have lost the opportunity to either distinguish it or say why it should be reversed.
Second, you will lose credibility with the court – something that will hurt you in all future cases before that same court. Thus, you may win a single battle (if the both the judge and the opposing counsel miss the case), but then risk losing a war that will be fought over the rest of your career.
Remember that the goal of a zealous advocate is to win the court rulings you should win, lose the rulings you should lose, and win as may of the discretionary rulings that you possibly can. Judges do not give discretionary rulings to lawyers who lie, cheat, or otherwise show disrespect for the court.
For an example of a judge really coming down on lawyers who ignored their obligation to cite adverse precedent, read this opinion by Judge Posner. It gets worse from here; "When there is apparently dispositive precedent, an appellant may urge its overruling or distinguishing or
reserve a challenge to it for a petition for certiorari but may not simply ignore it ."
Judge Posner called-out the offending lawyer by name. Here is the lawyer’s response.