§ 701.4 Owner registration cards.
Primary source
Verbatim text below is from the Electronic Code of Federal Regulations (eCFR), a public-domain U.S. government work. Always verify the current version with the eCFR before relying on it for any legal matter.
Full Text
When a warrantor employs any card such as an owner's registration card, a warranty registration card, or the like, and the return of such card is a condition precedent to warranty coverage and performance, the warrantor shall disclose this fact in the warranty. If the return of such card reasonably appears to be a condition precedent to warranty coverage and performance, but is not such a condition, that fact shall be disclosed in the warranty.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.