On a project, it is critical that all stakeholders understand their roles and the approach the project is taking. Understanding how all the different roles will be working together keeps the project running smoothly.
This is a process that needs to be continually revisited. Each stakeholder has their own understanding and their own perceptions. These will lead the stakeholders to start thinking differently about the approach as they gain experience on the project. Continually reinforcing the overall approach will catch these small differences in the perceived approach before they get too big.
A project is one team that requires consensus on approach from all members.