Anyone who "knowingly and willfully" conducts or participates in a meeting without complying with every part of the Act is guilty of a misdemeanor punishable by a $500 fine. O.C.G.A. § 50-14-6. Failure to give adequate notice can result in the invalidation of the proceedings, the issuance of legal injunctions, and the requirement to pay the objecting party's legal costs. See Slaughter v. Brown, 269 Ga. App.