Chit chat while being towed doesn’t actually violate the U.S. sterile cockpit rule that only activities necessary for safe operation of the aircraft can be carried out when below 10,000 feet (technically, during critical phases of flight). However they’re being recorded.
What’s unusual is standing in the cockpit for takeoff. U.S. rules are clear that pilots must be belted in at the controls, and everyone else has to be belted in for takeoff and landing. There is no standing in the cockpit.