In the event of an accident where other insurers are both admitted to each other, and no identified liability, they will share the costs in proportion to the cost of the handset without bonuses.
But there is a light at the end of the tunnel. A driver of the maximum allowed number of years had no bonus and have his first accident, do not stand to lose some of the insurers. Instead, the handover of a retreat a few years, for example, a reduction of five is to two years. It is advisable to pre-check this with the insurer to ensure that in its policy to advance a bonus.
It is possible to protect the bonuses paid to him, but there is not much in popularity because it increases the car insurance premiums in most cases.