While his statement about the driver being at fault may be out of place the part about mgmt asking what he could have done to avoid the situation is dead on.
As long as you put it in context... meaning - how do we minimize the risk of this happening in the future and not from the POV of what did the driver do wrong?
It would be interesting to hear from someone who is currently in Security.
I know that certain high risk areas such as the jewelry district in NYC had guards on the car with the driver. There are also drivers who have a car that tails behind them in high risk areas. In other high risk areas, the customers meet the driver in a neutral location that may be protected by one of the means I described above.
Every problem or challenge has a solution, I am sure there will be procedures set up to minimize future risk.