From Charles Kuralt's 1995 A Life on the Road:
With respect to my own appearances on camera, we have adopted the Tricycle Principle. We were somewhere in the midwest, watching the local news on the television set in the bus before going out to supper. There was a feature about a children's tricycle race, cute little toddlers pedaling away and bumping into one another, an appealing story pretty well filmed and edited.
Izzy said, "You know what? Before this is over, the reporter is going to ride a tricycle."
"Oh, no!" I said. "That would ruin the whole thing."
Sure enough, the reporter signed off in close-up with a silly grin, the camera pulled back to show that he was perched on a tricycle, and he turned and pedaled clumsily away, making inane what had, until then, been charming. The anchor couple came on laughing to sign off the show.
The Tricycle Principle is simple: "When doing a tricycle story, don't ride a tricycle." The story is about children, dummy, not about you. Keep yourself out of it. Try to control your immodesty.
Even when some guy in a bar is buying you a beer.
Even when a smiling stranger comes up to you with a grease pen wanting you to autograph his chain saw.