They said no to that because it would block too much traffic. We tried a locked mailbox once, until they ran it over with the snowplows and then people just took the mail off the street.
I should also point out that they allowed a school bus dispatcher to go in after condemning a amusement park. All the neighbors didn't want it, but we lost. We demanded a sign go up that says All commercial traffic must turn left. sign to direct them to our non residential road and use a county road. Even though they did that and there is a city ordinance about it, all the buses turn right to go through our street. So every morning there is about 150-200 buses in a long string blocking traffic trying to leave the neighborhood. You get high on the diesel fumes in your car as they pass by.
They aren't the brightest people.