[SampleMan]

Because if you total all four cars it will cost the insurance company a lot more than if you total only one.

That is not liability insurance. That would be collision insurance. Liability is for the damage I cause. I cannot cause damage in more than one car at a time.

And don't say it is because I can cause more damage in subsequent accidents, because my liability on one car covers me when I'm in a rental.

[calcowgirl]

Oops... good point.

In that case, I have no idea! ;-)