With children getting ready to go door to door trick-or-treating Monday for Halloween, communities near Los Angeles are taking action to protect their children from sex offenders and other criminals.

Riverside County passed an ordinance Oct. 16 prohibiting sex offenders from opening the door to trick-or-treaters on Halloween, turning their exterior lights on after dark and putting up Halloween decorations on Oct. 31.

Orange and San Jacinto cities have similar rules.

The ordinance states that “the events of Halloween could put children unknowingly in close proximity to sexual offenders who have committed violations against children.”

“Usually we have the predator going after the prey, but Halloween causes incidental contact between the prey coming to the predator, and so I want to minimize that contact,” Riverside County Supervisor Jeff Stone told ABC station KABC-TV in Los Angeles.

“These ordinances have been on the books in the cities of Orange and San Jacinto, and to my knowledge there have been no challenges, but we’re always up for the challenge if somebody wants to challenge it, I’ll always err on the side of children’s safety,” Stone said.

If sex offenders are caught in violation of the new ordinance, it will be considered a misdemeanor.

ABC News affiliate KABC contributed to this report.