[MQAAord]

I seem to remember Eagle's checklists calling for seatbelts/shoulder harnesses fastened.

If you do end up on takeoff roll without your shoulder harnesses fastened, you continue the takeoff, and buckle up asap.

My instructor and I were practicing maneuvers one day, and my shoulder strap had come undone. In the middle of a turn-about-a-point he says "hey, you're missing your shoulder belt". I look, say "oh yeah, I am", and proceed to re-buckle the shoulder harness while continuing the maneuver. He shakes his head and says "well, if you can handle a distraction like that, and continue and complete the maneuver perfectly, we don't need to practice that one anymore".