Freight trains are sometimes illegally boarded by individuals who do not have the money or the desire to travel legally, a practice referred to as "hopping". Most hoppers sneak into train yards and stow away in boxcars. Bolder hoppers will catch a train "on the fly", that is, as it is moving, leading to occasional fatalities, some of which go unrecorded. The act of leaving a town or area, by hopping a freight train is sometimes referred to as "catching-out", as in catching a train out of town.