A few weeks ago a fall of my wheelchair because I did not have any belt on and inertia caught me unawares as I let flying. It is one of those times I have reminded exactly what having cerebral palsy really means and that I do really need a seat belt and ideally a harness, as well as a helmet, for my own safety as well as my own comfort.
In the same way I have always needed a wheelchair throughout my life, to support my moving, I have also need some kind of harness for the wheelchair. For me, any harness is useless if not dangerous without the fifth strap, the crotch strap. The strap stops me submerging down the seat of my wheelchair and avoids any possibility of strangulation from the other straps. I also much prefer a full five point harness than the more fashionable butterfly style harnesses which I have never got on with.
Harnesses are just part of my everyday life, along with many other disabled people, which makes our life easier and safer.