My son's a T6 IP...happens to be visiting home on leave this week.
I asked him (when momma bear wasn't around, and hopefully she doesn't come across the news report) if he had heard about it yesterday, of course he had. There were issues with the explosive charges that grounded much of the fleet just two years ago, so we'll have to wait and see on this. Just asked him if he'd heard anything further through the grapevine, negative. As the pin needs to be removed prior to being able to pull the ejection handle, and there's certainly no reason an experienced T6 pilot would do that on the ground- seems probable to me that this was some sort of malfunction as a zero-zero ejection is typically survivable if it is intentionally initiated and the pilot is properly positioned. Hopefully the investigators will determine the cause in very short order.
Prayers for the family and loved ones of Captain John Robertson, may he rest in peace.