To be honest, unless you are planning to have an accident for insurance claims, (Which I doubt you would) You would have more chance being thrown off a Donkey on Blackpool beach than you would having an accident with the baby on board and the glass shattering causing cuts.
It may be just piece of mind, but I wouldn't bother. I have gone through parenthood and have many friends who have too, I can't think of any of them who have had an accident where the little passengers got hit by flying glass. Come to think of it I don't know of any of them who had an accitent worthy of being called an accident where the impact was enough to break glass.
But that is just me.