In article , tony
wrote:

Never having jumped out of a perfectly good airplane, nor having had people
bail out of my M20J, I'm ignorant re carrying jumpers. Do they belt themselves
in place during take off and climb?

The belts are there, but it is probably left to the individual as to
actually using them. Once airbore the jumpers can usually get rather
quickly (practice, practice, practice).
We had a bird nest in the engine compartment of our club 180 early one
Spring. As the plane was climbing to altitude with the first load of
the day, the nest began to smolder and smoke began waifting into the
cabin.
The pilot, scanning the panel and looking down towards the rudder
peddals, started to say, "Boys, I think we got a ..."
By that time, all five jumpers were out the door and gone!