Even then you have to be careful. I remember my dad telling me
about a case involving
two neighbours of his, a father and son. They were both going
out for the day and
decided it would be a novelty to drive each other's cars, so
they set off, one
following the other. Neither were covered by each other's
policy, but they each had
third party cover to drive any car on their own insurance, so
they thought it would
be ok. The dad driving in front (in his son's car) had to
brake suddenly, and his
son (driving his dad's car) ran into the back of him. It
turned out that neither
insurance company would pay up for the damage to either of the
two cars - they
weren't happy, to put it mildly !
They should have swapped cars after the accident. Then no problem. :-) Mike.