I bring this up because I remember this being one of the big complaints about the current patent system, and "peer-to-patent" would appear to make that even worse.
Secondly, patent attorneys don't like their clients doing any sort of search of/reading of any patents that could potentially affect their work. If you're found to have knowingly violated a patent, the damages are far greater than if you did it unknowingly. Submitting prior art to try to get a patent thrown out before it's granted would necessarily require researching and reading up on those very patents, so if the patent didn't get thrown out and you were eventually sued for infringing it, you'd be in much, much bigger trouble. Presumably the people who have the incentive and knowledge to bring up that prior art are likely to be involved in the same segment of the industry, which puts them in an awkward position: do you try to get the patent thrown out ahead of time, and be in serious trouble if you fail, or do you hope you don't end up at trial but keep the prior art in your back pocket in case you do?
Perhaps big companies could have a dedicated legal arm to research and challenge such patents at arms-length from their developers and/or keep their developers aware of potential minefields, but for smaller companies you'd be better off avoiding patent searches or research altogether.
That's fairly paradoxical given that patents are supposed to further innovation by giving people an incentive to disclose their inventions, but that's what the software patenting world has come to . . .
At the margin that's indeed a concern.
Many patent attorneys think, however, that --
A) On average you're likely to get a better take on patentability from an examiner, who has at least some background in the technology and who doesn't have a presumption of validity to overcome;
B) Suppose you have prior art that you think invalidates the claims of a patent application, but you withhold it from the patent applicant in hopes of using it later on as a defense in infringement litigation. The patent owner's trial counsel is likely to argue to the jury that your actions then speak louder than your words now. "If the prior art was so great," counsel will argue, "why didn't they give it to the patent applicant to be forwarded to the patent examiner? They're just trying to pull the wool over your eyes, and making you do extra work evaluating this supposedly-great prior art reference, when they could have saved you the trouble by having the examiner look at it in the first place."
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.
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.
The insidiousness of ignorance...
IANAL