Does the latter argument actually work in court? Is it the expectation of courts that people will continually monitor patent applications looking for things to invalidate?

That's how I've always understood it. The examiner is supposed to check for prior art, but (1) it's hard and (2) that cuts into revenue. The fallback mechanism has always been the patent appeal - generally the appellant has an interest in voiding the patent or some of its claims for business reasons, but there's no reason you have to.

So yes, it's the expectation of the courts that people will continually monitor granted patents and appeal them as necessary. And I guess patent applications as well.

> So yes, it's the expectation of the courts that people will continually monitor granted patents and appeal them as necessary.

I dunno about that. My sense is that a patent owner's counsel would not try to argue that the accused infringer had a general duty to monitor pending applications or issued patents. The argument would be, instead, that the circumstances suggest that the prior art in question wasn't so good after all.

Keep in mind that jurors are usually non-technical. Therefore, patent litigators try hard to find understandable indirect- or circumstantial evidence that can get the message across to the jurors. EXAMPLE: If someone walks into the courtroom in a dripping-wet raincoat, that's indirect evidence of rain. EXAMPLE: Widespread imitation of an invention, or praise for it, is regarded as indirect evidence of nonobviousness.

In this hypothetical, the patent owner's counsel argues that the defendant's failure to bring the supposedly-killer prior art to the attention of the patent examiner is indirect evidence. Of what? That the prior art wasn't so good after all, and that the defendant is trying to put one over on the jurors.

Wow. This goes to show you how easy it is to overestimate what you know - my patent experience is all about translating stuff from German (or French) into English, so now that I think about it, all the appeal documentation I've ever seen has been before the European patent appeals court. The thought of defending a patent in front of a "jury of your peers" is frankly something I never even thought of.

The insidiousness of ignorance...

The way I've heard it, patent examiners must meet high quotas. Rejecting too many applications and fighting the inevitable appeals (which isn't counted equally as useful work for some reason, possibly because it doesn't bring USPTO very much revenue) can cost them their jobs, while there are basically no consequences (at least not for themselves or USPTO) for rubber-stamping applications that should rightfully be rejected. If your prior art can only be seriously considered one time, that's not who you want doing it, however qualified they might be.