In days gone by UK military aircraft were tested for canopy jettison / abandonment / ejection seat function at the Blower Tunnel facility at Boscombe Down using both dummies and live subjects. None of the Grobs ever went through the process, if they had maybe the difficulties with canopy jettison that led to the fatalities could have been discovered before rather than after the event. It'll never happen now as the Blower Tunnel is no longer in service and is due for removal.