How can paramedics tell if someone's fainted or faked?

Where I'm from we call it "fluttering eye syndrome" and use a simple test to determine this. The paramedic applies a light touch to the corner of the pt's eye if the pt is truly unresponsive you will likely get no response if the pt's eyes flutter the sensorium is intact. A follow up technique here can be to lean in and whisper to the pt "I know you can hear me and i need you to wake up and talk to me because if not I'm going to have to start an iv and give you some drugs i don't know if your allergic to."