I saw something very similar to this when a car tryed to leave the underground car park in a rush before the security ramp had been fully lowered. What damage it caused, Hope the driver was fully comp!!.
Whilst most applications will be to enable the passage of one vehicle at a time, there will be instances where two or more vehicles attempt to pass through in close succession. The system should ensure that bollards cannot rise beneath a vehicle because of the danger this would create. It is better to risk a certain amount of violation by "tailgating" vehicles, rather that put road users at risk.