if the bus operator has planned his workload properly he should have sufficient capacity to soak up delays
You'd think, wouldn't you; although I suspect if the pricing pressure is anything like VS, then they don't have spare buses at peak times, nor spare drivers sitting around with nothing to do. One of the problems of negotiating suppliers down to the wire is that leaves them little margin for error when things go wrong (and unplanned surges in demand, due to things such as delays would often be out of their control).
But this is thread creep, and I wouldn't want to upset the forum gods
