Grier discussed Proposition S on Tuesday night during a meeting that some principals said they felt compelled to attend, the newspaper reported.

School districts may use taxpayer money, employees and other resources to educate the public about a bond initiative, but it is illegal to use those resources to advocate for a vote, according to the newspaper.

Principals were notified about Tuesday's meeting via "urgent" e-mail messages sent the day before, the Union-Tribune reported.

University City High School Principal Michael Price told the newspaper that it was clear that some of the 70 or so people were uncomfortable during the meeting, which took place at the San Diego Girl Scouts' headquarters in Balboa Park.

"I personally did not feel pressured, but I am at the end of my career and I already support Proposition S," Price said. "My concern was that it took time away from my school."

Three other principals apparently told the newspaper that they did feel uncomfortable but asked not to be named for fear of retribution.

During the meeting, Grier called on people to help with a phone bank on behalf of the proposition, the Union-Tribune reported.

School board President Katherine Nakamura defended the meeting and said it was optional, according to the Union-Tribune.