If you have a great team leader, your event staff team will fall neatly in line. You can have the most extraordinary talent for staff, but if their event captain is inexperienced, or not present at all because you forgot to hire one, you are putting yourself in a risky situation.
Staff members often need direction, especially when it comes to preparing events that involve more than one kind of staff member. You need someone in charge to coordinate and oversee to make sure that the timeline is being followed, the tasks are all being met, and the quality is peerless.