A "patent", according to Wikipedia, is "a set of exclusive rights granted by a sovereign state to an inventor or assignee for a limited period of time in exchange for detailed public disclosure of an invention." Yet no one engaged in the business of developing technology ever reads patents for R&D purposes. The reason? Knowledge of a patent enables the patent-holder to claim willful infringement, and willful infringement opens the door to enhanced or even treble damages.
I know of many technology companies with rigorously-enforced policies prohibiting engineering staff from reviewing competitor patents. I was involved in an asset purchase transaction recently in which the acquiring company's in-house lawyers refused to allow their staff to review the very patents they were buying, in case the deal failed to close. This fear of enhanced damages, whether justifiable or not, effectively nullifies the patent system's invention disclosure justification.