Yes, it is a prerequisite --- In my few years in the sport, I've heard many people proclaim that they are going to go BH, 1 & 2 in the same multi-day trial ---- and it just doesn't happen that way. But my experience is limited. You can do it so long as it is on different days of the same trial. But if they run BH first thing in the morning, then do tracking or obedience afterward, it's not going to work. One club I know will do BH, obedience and protection in the evening, then tracking the next morning. So it can be difficult to find a venue set up to let you do this.