PFDs are like seatbelts in cars. With the newer ones, there really is no excuse for not wearing one... All it takes is a bump on the head which knocks you out, and the best swimmer will drown when thrown overboard...
They have not released any more details about this accident, and the news cycle has moved on. Maybe, we can find more info through the local reservoir police dept., so that a similar event might be prevented in the future...
Prayers for friends and family....