Why doesn't a bank have to cash a check that is drawn on them?
There is no federal law or regulation that requires a bank to cash checks for noncustomers. Most banks have policies that allow check cashing services only for customers who have an account with them in order to protect both themselves and their customers from forgeries.
Once a bank cashes a check that has been forged by a noncustomer, they may lose money if they cannot collect from the person who cashed the check.
Also, if a bank agrees to cash a check for a noncustomer, it may legally charge the presenter a fee.