I think it can also have to do with the fact that an instructor wants to make sure there is a solid grounding in basics, strategy and tactics before letting them out there to bang away and start creating bad habits. In many schools there is one-step, and three-step sparring (kumite) that is done before free-sparring is introduced. In Kajukenbo, we opt for pre-set counters with ad-libs to accomplish the same effect. You need to know how to move before sparring or you just get sloppy IMO.
Absolutely!