As a human performance scientist, I have learned that humans only perform to deadlines.  One of the reasons that deadlines influence behavior is that deadlines define and clarify responsibility.  Deadlines also introduce a feedback loop of accountability.  Responsibility and accountability are fundamental to human achievement.

In his clever book on human motivation and performance called You Really Oughta Wanna, Robert Mager discusses the importance of accountability on human performance.  He argues that if no one ever asks for an accounting of assigned responsibility, the quality of performance on that responsibility will erode and eventually terminate.

When you schedule the next event it sets a deadline for you and your suspect.  It governs the behavior of sales people as well as the commitment of your suspect.  Scheduling creates a deadline and accountability.  Deadlines and accountability govern human performance.