We are not aware of any Illinois law that requires banks to cash Social Security checks and IRS refund checks for non-customers. Of course, an individual who is 65 or older who is denied the right to cash a Social Security check at your bank may request that you establish a Basic Checking Account for him or her, and in such a case, you would have to cash the check (after opening the account).
The Illinois Consumer Deposit Account Act, at 205 ILCS 605/4, requires banks to offer a “Basic Checking Account” to people who are 65 years or older who request such an account. The terms of Basic Checking Accounts, such as fees and minimum balance requirements, are established by the statute and are very favorable for the customer.