I'm going to guess that management of the site has been contracted out to the private sector, and somebody at this management company has put the signs up witho

I'm going to guess that management of the site has been contracted out to the private sector, and somebody at this management company has put the signs up without really understanding that this may not be technically right. However, it'll probably take some sort of arrest/court case to get some clarity on this, so chances are it'll just be like this for years without ever being properly challenged.