Mr Enders and his Jump
I agree that 6 and then 10 parachutists having jumped from Grizzly does not prove anything other than to provide some information to the development and clearance teams. However, perhaps the fact that Tom Enders has done it can be seen as a corporate gesture of confidence in the product - a thought to be modified by any sane aircrew man's view of jumping out of any serviceable airframe.
In the old days when some engineering work led to the requirement for an air test it was common for the techy(ies) concerned to fly on that air test as a gesture of solidarity (and, no doubt, pour encourager) - could not TE's jump be seen in a similar light?