I think you have to have a special connection with your horse to be able to ride without a bit. Some people *need* a bit to "control" their horse. But if a horse is willing to lend you his legs, and his mind connects with your mind, it should be a ride that does not need any pulling or yanking on the reins.
This article should help owners get to the point of connecting on a different level with their horses: http://paintinghorse.wordpress.com/what-is-attraction/
