Illinois is one of several states where law prohibits registered sex offenders on parole or probation from handing out candy to trick-or-treaters for Halloween.
The Chicago Tribune says if no one is at the home of a sex offender officers plan to slap a big red tag on the door "a visible sign that police have been to the house."
Chicago police want neighbors to call if they see a known sex offender handing out candy.
More than 6,300 registered sex offenders in Wisconsin are not allowed to answer the door during weekend trick-or-treating hours under decade-old rules by the state Department of Corrections.
In Texas, police and probation officers notified sex offenders of a Halloween curfew that bars them from decorating premises or turning on porch lights for trick-or-treaters.