Police in three West Texas counties have ordered all convicted paedophiles to turn off their porch lights and not to answer the door during Halloween.
Convicted sex offenders whose victims were children and who are on probation must be home by 6.00 p.m.
Officers in Lubbock, Potter and Tom Green counties will check on the 100 or so men and women throughout the night as part of Project Lights Out.
Statewide, parole and probation authorities will increase their surveillance of sex offenders during the weekend, said a Texas Department of Criminal Justice spokesman.
Such programmes are a great idea, says mr Marc Klaas, whose daughter, Polly, was abducted from her California home in 1993 and found murdered. Otherwise, he said, "it's like Santa Claus knocking on your door if you're a pedophile."
Last week, letters went out to sex offenders in Lubbock County whose victims were children. The reaction has been mixed.
"Some are doing it willingly, some are complaining about it," said Mr Steve Henderson, director of adult probation.
One 28-year-old sex offender, however, said he thinks Project Lights Out is an appropriate safeguard. "There's no reason for kids to be going to our houses anyway," he said.