5 warnings for a credit card co-signer
The bill is yours
When you sign that credit card contract, you're saying, "If anything goes wrong, I'll pay the balance. All of it. Plus interest and penalty fees."
You're not acting as a reference. You're not "loaning out" your good credit. You're not promising to tell bill collectors where to find the account holder. You're not offering to split the bill or help them catch up if they fall behind.
You, (the person with good credit) are promising to pay the entire bill because the lender doesn't think the applicant is quite up to the task.