Bylaws are live by laws. They relate to occupiers living together and get referred to when someone does something offenses or disruptive. Your state’s Act outlines things relative to who can do what to your sites shared owned asset. Your committee is formed to administer the upkeep of the buildings and its global issues. Regarding your gate: it doesnt require a bylaw at all and to get it changed it should be preseyted to your committee for their approval and record of the decision to help the integrity of the building and help stop a bunch of individual owners all negatively and piecemeal fashion devaluing your building. But that said if they are nuts and no one sees it anyways, if you just swap it over they may not even notice its done. But if you do that help your own cause by choosing only something that complements the building and keep the old gate incase they discover it was you and demdnd the original be reinstalled.