www.doe.mass.edu/lawsregs/advisory/cori.html
In Massachusetts, it is law that all people working with kids ( volunteers included) must have a CORI check ( criminal record check).
For those in mass, the link is above, and an excerpt below:
Overview of the New CORI Law
Chapter 385 of the Acts of 2002, An Act Further Protecting Children, was enacted into law on November 27, 2002. The purpose of this advisory, prepared by the Department of Education in cooperation with the Criminal History Systems Board (CHSB), is to inform all public and private schools1 about this new law and its requirements, and to present certain issues that must be considered by schools as they work to comply with the law, which takes effect on February 25, 2003. A copy of Chapter 385 is available for your reference at
www.state.ma.us/legis/laws/seslaw02/sl020385.htm.
Section 2 of Chapter 385 amends M.G.L. c. 71, § 38R to require that all schools conduct criminal background checks on current and prospective employees, volunteers, school transportation providers,2 and others who may have direct and unmonitored contact with children. Criminal offender record information ("CORI") must be obtained from the Criminal History Systems Board (CHSB) - the state agency authorized to provide CORI to certified agencies - at least every three (3) years during an individual's term of employment or service. In addition, schools may perform CORI checks on subcontractors or laborers commissioned to do work on school grounds who may have direct and unmonitored contact with children.
M.G.L. c. 6, § 172I also requires schools obtain CORI data of employees of taxicab companies that have contracted with the schools to provide transportation to pupils pursuant to M.G.L. c. 71, § 7A. Contracting taxicab companies are required to submit the names of employees who may have direct and unmonitored contact with pupils to the appropriate school committee or school superintendent prior to transporting any pupil.