Clontech held that such an intent is inferred if the relator shows "by a preponderance of the evidence that the party accused of false marking did not have a reasonable belief that the articles were properly marked (i.e., covered by a patent)." This inference cannot be rebutted by a patent owner's mere assertion that it had no subjective intent to deceive.
After Clontech, filings of false marking suits jumped significantly. Cases were filed by large firms, solo practitioners and public interest organizations. Defendants have included Gillette (for alleged false marking on razor blades), Solo (plastic cup lids), Brooks Brothers (bow ties) and Target (closet organizers), according to Elizabeth Winston, assistant professor at Catholic University's Columbus School of Law.
The Federal Circuit in Forest Group tried to limit the danger posed by trolls. The court noted that violators of the statute need not be hit with a $500 fine for every single falsely marked item. Five hundred dollars was the maximum fine per offense, and district courts could impose far less. "In the case of inexpensive mass-produced articles, a court has the discretion to determine that a fraction of a penny per article is a proper penalty," the Federal Circuit stated.