Yes ScenicViewer:
It does matter if more than one person knows about it and each are mandatory reporters. In California the statute prescribes the following when multiple mandatory reporters:
When two or more persons, who are required to report have joint knowledge of a known or suspected instance of child abuse or neglect, and when there is agreement among them, the telephone report may be made by a member of the team selected by mutual agreement and a single report may be made and signed by the selected member of the reporting team.
Also in some states it is required that the information be transmitted to the person in charge and that is the extent of the reporting requirement.
If a person is required to report child abuse because that person attends to a child as part of the person’s duties as an employee of or volunteer at a hospital, school, social agency, or similar facility, that person shall notify the person in charge of the facility, or the designated delegate thereof, and the person so notified shall report or cause a report to be made in accordance with this section. An employee or volunteer who makes a report to the person designated shall be deemed to have fully complied with this subsection