I have heard that cars with fabric upholstery will catch on fire readily, and in fact have experienced that first hand. My girlfriend had a Jetta and some guy stole it, left a newspaper in the front seat and lit it and that was enough to torch the whole car.
Now, however, I have a car with leather seats, so I assume that just lighting a newspaper and leaving it on the seat won't work because leather doesn't burn very well. Is that right, or is my car vulnerable to fire even though it has leather seats?