You Park On Street Directly Across A Driveway

Most people/drivers who have to back out of their driveway, unless on a busy street, don't pay much attention to parked cars as in most cases there is no car parked directly across their driveway.  If you park there he may very well back into your car, especially if he is going in the direction of the opposing travel lane.  Even if he notices your car and doesn't hit it, or shoot out your tires, it's harder for him to negotiate around your car - which is not fair.  So be a good neighbor and if you have to park on the street do so where it won't interfere with his turning radius.  As good fences make good neighbors, courtesy goes a long way towards that end.