I did I used to give lectures in conjunction with the RAC for companies in which a famous example was a young man who had a motorbike which was insured for travel to a regular workplace (SDP&Commute) anyway at the end of a day (he worked at a Royal Mail depot) the lad was asked to drop off a parcel to another depot on his way home.
Unfortunately the lad was involved in accident and killed on his way to the other depot.
The Royal Mail was fined a very very large amount for the incident as the lads insurance was made invalid as he was not travelling directly home but via another branch.