No, there is no legal risk to recording a meeting as it is an open public meeting. Many different groups record their meetings. It is also a tool used by secretaries to help them with their minutes.
I am new to the whole PTO thing and am on the board at my daughter’s school this year. It is a brand new board with very little experience. There has been discussion about recording the meetings. If we do record the meetings are we putting our selves at legal risk?