This would not seem to violate the federal anti-tying provision of Regulation Y (https://www.newyorkfed.org/banking/circulars/11230.html) as it would meet the “traditional bank product” exception. As to whether it would be a considered unfair under UDAP/UDAAP you would have to look at the definition/criteria of “unfair” – and I would suggest to also evaluate the product for “abusive” or “deceptive” triggers as well – and compare it to your product (along with associated processes, disclosures, verbal communication, advertisements, etc.) to avoid potential issues. Another potential issue you should consider is fair lending – could this policy have a disparate impact on certain protected groups (i.e. are minority groups less likely to have a checking account and therefore less likely to qualify for the product/favorable pricing because of this policy)?