Aerospace engineer here. Absolutely, weight distribution is a major safety concern especially during takeoff and landing, which is why they have people stay in their seats during both, and also why the baggage area is netted in to compartments. If you've ever been on a flight that is only at half capacity they can and will move people around, otherwise you get something like this happening. If you ever see hambeasts (su  6e0f  rprisingly) become mobile during a takeoff or landing procedure, for the love of your life and others please alert a flight attendant so they can wedge their fetid masses back in to their seats.