The daily Scrum is a private meeting for the team members to report status to everyone else on the team. In many respects this is very similar to the regular private status meetings an employee has with their boss. It is rude and inappropriate for people to come into this manager/employee meeting. It is even ruder if a third party came to this private meeting and started making all sorts of suggestions or demands of the manager or employee. The privacy of this meeting is required to build trust between the manager and the employee and for both parties to be able to speak freely without embarassment... The daily Scrum should be considered exactly the same way with the one exception that the Team has graciously allowed observers to also attend. This is why observers are not allowed to speak during the daily Scrum.