For kids, the Halloween season signifies candy and costumes. For probation departments, it was serious business as they monitored hundreds of Long Island sex offenders who might be tempted to use dress-up and trick-or-treat to lure potential victims.

For the seventh year of “Operation Safe Sweets,” the Nassau County Probation Department conducted random home visits or phone check-ups of 300 sex offenders in the county in the days leading up to Halloween and on the holiday.

“You can’t celebrate the holiday. You can’t decorate your house. You can’t wear costumes. You can’t open your door,” said Director John Fowle.

Failure to comply could result in imprisonment.

Alfred O’Connor, an attorney with the New York State Defenders Association, said these nationwide programs were “an overreaction.”

“There’s no documented case of a sex offender molesting a trick-or-treater,” he said, citing a 2009 Lynn University study that found “no significant increases in sex crimes on or around Halloween.”

John Desmond, director of the Suffolk County Probation Department, said they constantly monitor some 395 sex offenders year-round.

“We’re not just looking for this activity one day a year,” he said.