When sealed bids or proposals, or oral bids, are accepted for the purchase or lease of the property of a local government:
1. Any agreement or collusion among bidders or prospective bidders in restraint of freedom of competition, by agreement to bid a fixed price or otherwise, is unlawful and renders the bids or proposals of the colluding bidders void.
2. Advance disclosure of any information to a bidder which would give that bidder an advantage over another bidder, if made or permitted by a member, employee or representative of the governing body renders all bids or proposals void.