In Medford, Oregon (MFR) I was asked to open my backpack so that they could confirm that there was a camera in there. They didn't pick it up or look at it, just seeing it was enough. In San Diego they didn't do anything about it, going through the x-ray was enough for them.
My camera had my Tokina 28-210mm lens attached, and also in the backpack was the Canon 35-80mm lens, and several rolls of Reala and a roll of Kodachrome.
David / SAN