Re: This is normal in every human endeavor.
I did that at a convention I was working- the room that I was lugging gear into had presence sensors set up for the lights, and I had a helper with me as we pushed our cart full of gear to set the room up. I pushed the cart in about 6 feet, yelled "AZIZ! LIGHT!" and as I snapped my fingers, BOOM! the lights came up. It was timed just enough that my helper cleared two feet straight up from the surprise.