The U.S. Supreme Court case Karen L. Jerman v. Carlisle, McNellie, Rini, Kramer & Ulrich LPA et al., 2009 revolved around the Fair Debt Collection Practices Act (FDCPA). The plaintiff, Karen Jerman, sued a law firm for violating FDCPA by including an incorrect statement in a foreclosure notice that she had to dispute the debt in writing. The defendant argued they should not be held liable as they believed their actions were legal due to bona fide error defense - a provision which protects debt collectors from liability if they can show that the violation was unintentional and resulted from a factual mistake rather than misinterpretation of legal requirements under FDCPA. However, the Supreme Court ruled against them stating that this defense does not apply to mistakes of law but only applies to clerical or factual errors.

In the dissenting opinion for Karen L. Jerman v. Carlisle, McNellie, Rini, Kramer & Ulrich LPA et al., Justice Scalia argued that the Fair Debt Collection Practices Act (FDCPA) should not be interpreted to exclude a defense of bona fide error when it comes to legal mistakes. He contended that such an interpretation is inconsistent with common law principles and could lead to unjust results by punishing debt collectors who make good faith errors in interpreting complex legal requirements. Furthermore, he suggested that this narrow reading of the FDCA might discourage debt collectors from seeking out and relying on legal advice in their operations due to fear of liability for potential errors made by their attorneys.