My nephew took his family and his mother (my sister) on a tour of the White House a few weeks ago. They were in the East Room, and a Secret Service agent stood guard there.
My 3-year-old great nephew Finn stood right in front of the agent, looked up at him and asked, "Are you a policeman?" The agent squatted down right face to face with Finn, and in a Texas drawl responded, "Something like that."
Finn then grabbed the agent's face in his hands, one hand on each cheek, and fuzzed the man's beard scruff. The agent startled a bit, of course, but stayed there, and said, "Nobody has done that to me since my grandma." He said it sternly, but there was a smile in his eyes.
This photo was taken just a few seconds after that interaction.