Are charges of inequitable conduct fairly routine in patent litigation?

Yes, in fact, at one point charges of inequitable conduct had become so routine that the Federal Circuit had referred to them as "an absolute plague" (Burlington Indus., Inc. v. Dayco Corp., 849 F 2d 1418, 1422 (Fed. Circ. 1988). Additionally, charges of inequitable conduct significantly drive up the costs of litgataion, "exploding" the complexity of these cases by sweeping in potentially thousands of new documents directed to the issues of what exactly the inventor knew and when the inventor knew it. Another quite nasty side effect about the inequitable conduct defense is that it causes patentees to behave in an overly defensive manner. That is to say, it causes patentees to overload the U.S. Patent Office with thousands of prior art documents of dubious value.

A recent article by Eric E. Johnson in the Columbia Law Review argues for eliminating the inequitable conduct defense altogether. That referenced article is provided below:

http://columbialawreview.org/content/the-case-for-eliminating-patent-laws-inequitable-conduct-defense/