William Cinfici (sin-FEE'-see) says waiving the fees associated with the April rally represents an in-kind donation to the Democrat's campaign. He says that's illegal and unfair to taxpayers.
Other board members say the decision to waive the fees is not illegal. School officials say they don't know exactly how much the fees would total.
Cinfici has asked the board's solicitor to look into whether it was legal.
Democratic Sen. Hillary Rodham Clinton held a rally at nearby Wilson High School and was charged $6,460. Clinton won the state's April 22 primary, but Obama has since earned enough delegates to be the party's presidential nominee.