If the loyalty account is based on a phone number, try entering your local area code plus 867-5309. I've found this works at every major supermarket and gas sta

If the loyalty account is based on a phone number, try entering your local area code plus 867-5309. I've found this works at every major supermarket and gas station. Sometimes you get slight discounts because other people also enter this number and the account accrues points. The other option is to sign up using a fake persona and a burner email. Typically rewards programs don't audit information or ever ask you to update it.