Security is provided at the BCC meetings, in the form of a Deputy. Having a metal detector wouldn't stop a psycho who was not scared of shooting the deputies at the metal detector station. Having deputies present obviously is not secure either. It is virtually impossible to have complete security, as there are failures in every system. If having a metal detector makes elected officials feel secure at public meetings, so be it, but it prevents only the truly stupid from acting out their threats.
There seem to be freaks who do crazy things, regardless of the business -- post office, financial centers, court houses, etc. We cannot protect ourselves from all freaks, and we need to realize that we shouldn't work so damn hard at limiting freedom in exchange for safety. Security is a false state of mind. Everyday, people drive on highways, eat food at restaurants, smoke, drink, take prescription meds, etc. We take our chances, but enjoy our right to eat a big, fat ribeye if we want. If Commissioners want to be safe, ask them not to drive on a highway to their meetings, because the chances of them dying in a car crash are likely much higher than getting shot at a County Commissioner meeting. Let's keep it in perspective.