Chick-fil-A CEOs have been doing this (if not more frequent) since inception
I'm there a lot (some would say too much, but I wholeheartedly disagree!), and it's odd to pass through without seeing him. He works the register, he takes orders in the drive through, he directs traffic in the parking lot, he carries orders out-- everything. I'm certain that he's done shifts in the kitchen as well, just that I couldn't seem him to know.
Just today, I went into the restroom to wash my hands and he was cleaning the stall.