Project plans should be visible by stakeholders. Project team members, senior management, customer should be able to follow milestones and deliveries regarding the progress of the project at any time.
The way to get the support of the project team members and keep the motivation high is to ensure that the plan is published in an environment that the team can reach easily.
Since the top management can easily follow the team's performance due to the openness of the plans, they can prevent quickly to any delay.
From a customer perspective; Companies that manage their projects transparently will be more preferred in the future.