yea I doubt the gate agent said anything to the crew... I have never heard an agent tell us "hey there is a OAL jumpseater wanting to get on...." especially in a hub.
I have even had been denied the jumpseat on skywest after talking to the captain and had him waving me to come out because the weights worked for me to sit up front but the gate agent (skywest gate agent) wouldnt let me out the door... (LONG STORY)... AND I WORK FOR SKYWEST...