It seems that one of the defining features of a patent troll is that they like to sit on a patent until a large, profitable, and well-established industry has b

It seems that one of the defining features of a patent troll is that they like to sit on a patent until a large, profitable, and well-established industry has built up around a technology that could be construed to fall under the patent's domain. At that point, they make their move for fame and profit. Would it be reasonable to require "due diligence" on the part of the patent holder in order for a patent to be considered valid? In other words, if they have shown no interest in protecting their intellectual property in the face of long-standing and widely known "violations," it seems that a situation could apply that would work in a way analogous to the idea of piercing the corporate veil. Patent holders who have sat idly by as the violations of their patents (pending or otherwise) have gained notoriety and fame have demonstrated a lack of desire to pursue the technology, and are obviously just using it as a get rich quick scheme. The idea here would be that, in this case, Personal Audio would have had to protect the rights to their setup as soon as it became reasonably evident that violations could be occurring (maybe the birth of iTunes or something). That would have been many years ago, before podcasting became popular. At that point, there's little profit in a lawsuit other than actually stopping someone from stealing an idea, so it's not so much of a bank account booster. This just occurred to me, so I apologize if it's been discussed and demolished before -- it does seem that it would help to prevent this sort of surprise attack from happening without harming actual legitimate patent holders (they will pursue their rights early and often regardless of this idea being implemented).