I have gotten both legitamite relay calls and scam relay calls. Usually the scam ones are very easy to detect as they will read from the same script as the scam emails.
There are 2 relay systems. IP RELAY and the STATE RELAY system. The scammers will always use the IP Relay because they do not have any access to the local State system.
When I suspect a scam I say: "Because this call sound like an attempt at fraud I need you to hang up and call us back using your State relay system" They always close the conection before the operator can finsh typing it out.
Bear in mind the operators who work a thankless job, and the disabled Americans who are discriminated against because the criminals have taken over their service. A service which is mandated by the FCC and paid for by you, by way of a fee on your phone bill.