The notice is the heart of this subject, and it is quotable because the regulation prescribes its words. 16 CFR 444.3(a) makes it a deceptive practice for a lender or retail installment seller "to misrepresent the nature or extent of cosigner liability to any person", and an unfair practice "to obligate a cosigner unless the cosigner is informed prior to becoming obligated ... of the nature of his or her liability as cosigner". Paragraph (b) then gives a safe harbor: a creditor that complies with (c) does not violate (a). And (c) requires "a disclosure, consisting of a separate document that shall contain the following statement and no other", given before the cosigner becomes obligated, which for open-end credit means before the agreement creating liability for future charges is executed. The statement reads, in part:
"You are being asked to guarantee this debt. Think carefully before you do. If the borrower doesn't pay the debt, you will have to. Be sure you can afford to pay if you have to, and that you want to accept this responsibility."
"You may have to pay up to the full amount of the debt if the borrower does not pay. You may also have to pay late fees or collection costs, which increase this amount."
"The creditor can collect this debt from you without first trying to collect from the borrower. The creditor can use the same collection methods against you that can be used against the borrower, such as suing you, garnishing your wages, etc. If this debt is ever in default, that fact may become a part of your credit record."
The third paragraph is the one people are surprised by, and it is the reason the common description of a cosigner as a last resort for the lender is unreliable. The notice also ends by saying "This notice is not the contract that makes you liable for the debt", so receiving it settles nothing about what the contract says. Read the contract as well.
What the rule's own scope is, stated as what the regulation contains. 16 CFR 444.1(a) and (b) define "lender" and "retail installment seller" as persons engaged in those businesses "within the jurisdiction of the Federal Trade Commission". So the Credit Practices Rule's requirements are addressed to creditors within that jurisdiction, and 16 CFR 444.5 additionally allows the Commission, on a state agency's application, to switch off a provision in a state whose own requirement affords protection "substantially equivalent to, or greater than" the rule's. If you are cosigning and no notice appears, the useful question is what the contract makes you liable for, not which agency's rule should have produced a form.
A separate statute limits who a creditor may ask for. The Equal Credit Opportunity Act's Regulation B provides at 12 CFR 1002.7(d)(1) that a creditor "shall not require the signature of an applicant's spouse or other person, other than a joint applicant, on any credit instrument if the applicant qualifies under the creditor's standards of creditworthiness for the amount and terms of the credit requested". Paragraph (d)(5) then allows the request where it is genuinely needed: if the personal liability of an additional party is necessary to support the credit requested, "a creditor may request a cosigner, guarantor, endorser, or similar party", and the applicant's spouse may serve, "but the creditor shall not require that the spouse be the additional party". And (d)(6) bars a creditor from imposing on an additional party any requirement it could not impose on the applicant. Narrow exceptions in (d)(2) through (d)(4) let a creditor require another person's signature on the specific instrument needed to reach jointly held property, community property or pledged collateral.
Put together, the rule is not that a creditor may never ask for a cosigner. It is that it may not ask when the applicant already qualifies, may not insist the additional party be the applicant's spouse, and may not hold the additional party to a standard it would not apply to the applicant.
What sits outside this page. Joint liability from the first day, cosigner release programs, and the statutory protections when a cosigner dies or files bankruptcy on a private education loan are covered by the published material on private student loans. The route for a card applicant under 21 belongs to the material on credit limits. And a guarantor is a related but distinct role whose liability depends on the terms of the guaranty and on state contract law, which is why nothing here states a general rule about it.