There's a fair lending issue, also.
These are the only type of consumer loans where the credit risk is identical from one borrower to the next--zero. With the risk controlled, all borrowers are equally qualified. Therefore, if prices and loan terms vary from one borrower to the next, you have disparate treatment. So...if one borrower is female and the other is male, old/young, minority/non-minority (you get the picture), then you're exposed to charges of discrimination on a prohibited basis. If you do these loans, then you have to maintain unwavering compliance with your lending policy in order to guarantee uniform terms and pricing.
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...gone fishing.