Our school is working on a few issues our school board has with parents that have caused problems while "volunteering." Volunteers are not allowed to grade papers, must be finger printed (for a background check) and MUST sign in at the front office and wear a name tag, this is just to name a few! I don't mind it and don't really think Johnny's Mom should know anyonelse's test scores!
Does your school have a formal policy regarding volunteer confidentiality (that is, a policy which reminds volunteers that they may learn information which should remain confidential and should not be gossiped about?)