"Stand up immediately after the plane lands" - not a very clear category. Are we talking about as soon as the wheels touch down and the plane is still taxiing, or as soon as it comes to a full stop at the gate?

I tend to stand up when the plane has stopped at the gate, because I get stiff sitting for too long and want to flex my legs a little before walking off the plane (the joys of arthritis), but then I wait at my seat until my row exits.