A must read article dispelling many of the myths surrounding "satanists" and "witches" sacrificing black cats near Halloween. Such urban legends arose during the satanic-panic hysteria of the late 1970s through the mid 1990s. As a result, many shelters refused to allow adoptions of black cats during the month of October. Some shelters went even further and refused to allow the adoption of any black colored animal in October.
A few years back I was pleased to read another story of a shelter who advertised their allowing of black cat adoptions because the owners recognized that the horrible stories of sacrifice weren't true.
The truth about black cats and Halloween