The short version of this story is that sex offenders in Maryland are required to post a sign on their door stating that candy is not available at that location. They are also required to stay at home, turn off their lights and not answer the door.
Maryland government is mailing the signs to the sex offenders as well as pamphlets to families advising them to avoid houses with the signs on them.
I truly support this and would love to see a similar program in Kentucky. Run a search against your area - you might be very surprised to see how many pedophiles live near you or your loved ones!