I was the Code Enforcement Manager of a City of about 600,000 inhabitants for the last ten years before I retired. Our Inspectors routinely placarded vacant unsecured buildings. Besides being an eyesore they present an attractive nuisance for the homeless, drunks, drug users, dangerous fires, and ganbangers. Our nuisance ordinances are written with a specific abatement procedure as set forth by state law in order to protect the public and preserve property values for abuting property owners. Generally an abatement order requires that the property be cleaned of all trash, junk and debris as well as being boarded up and or secured in a safe manner. It is the responsibility of the property owner to maintain the property up to code. If they don't, the City may declare the property a nuisance and proceed to do whatever is necessary to attain compliance. The charges for the work are collected by the city in the form of a lien in the amount of the fees charged. If the lien isn't paid within a specific amount of time the building or house lein may foreclosed on by the City and the property sold. All proceeds go to the City. It is also a criminal violation not to maintain your property and you may be fined and/or imprisoned not more than 90 days for every seperate violation. The placard is posted conspicuously on the property mainly to warn the public of the unsafe conditions and also to serve as notice to the property owner. I have attended conferences throughout the USA, and that is basicaly the same or similar procedure in each city or jurisdiction. Nearly all urban areas adhere to specific national property codes. Hope that helps understand how the system works. Onus