A friend recently retired from mini-cabbing. He initially struggled to get his no claim discount (NCD) carried over from his specialist cab policy to the ordinary policy. His broker suggested that if he added another driver the premium would automatically reduce by 30 per cent. He was told it did not matter if the second driver has no intention of driving the car and the lower premium was because multi-driver cars tend to be driven with more care than those used by more than one. He asked me if I was prepared to be named but I was concerned that there might be a potential downside for me and my personal NCD - am I being over cautious?