We do enjoy a construction fence that has been busted down (and many in Williamsburg can be opened by a 12-year-old) to allow access to a deadly building demolition site. So it is with 261 N. 9 Street this week, which is one of the sites in Williamsburg being developed by an owner of the Greenpoint Hotel. The building is within our Williamsburg Triangle of Death, a corner of the Burg where one can find more wide-open sites than ones that are closed, a number of them presenting clear threats to public safety, and no evidence of effective Department of Buildings enforcement.