Legal Question in Consumer Law in Illinois

Most businesses post such communications; in fact most senders assume that will be the case. The question is whether there is an expectation of privacy to the communication; if there's nothing that says it was intended as confidential, you should be ok. But the real question is why wouldn't you seek the approval? It may only take a phone call and would be courteous. It only makes it that much better for you.

You might be ok, but why would you? Asking permission gives you another chance to make contact with a customer who thinks highly of your company.