To the untrained eye, there was nothing nefarious about the packages that arrived at Camp Kennybrook containing a Harry Potter book, tampons and a flashlight.

Stacey Landman knew better. All of the items were vehicles used by parents to smuggle food into the Monticello, N.Y., camp she owns with her family—something that’s strictly forbidden since the contraband can attract bugs and mice and cause allergic reactions.

Sneaking outside food into camp is a tradition as old as color war. Generations of parents and campers have rolled Pringles tubes into towels and stuffed candy into tissue boxes and sliced-open tennis balls. Campers hide the goods in laundry bags, lockboxes and pillow cases.

It got so bad at Camp Westmont in Pennsylvania’s Pocono Mountains this year that administrators emailed parents on the second day of camp about the “shocking” abundance of food found in bunks that could lead to an infestation of mice and allergic reactions to nuts.

Each generation devises something new. Sites like Amazon and Etsy offer modern smugglers cheap and easy access to hollowed-out bottles of sunblock and hair spray that are meant to keep valuables safe while sunbathers step away from their stuff.

Despite the advances, Landman has a message for parents and campers: “We’re onto you.”

The Harry Potter book was hollowed out and filled with M&M’s, something Landman’s staff discovered because of the noise when the book shifted. The tampon box was filled with chocolate bars and reglued so it looked unopened. Counselors were tipped off by the unusually heavy weight. (Landman said she was impressed by the resealing job and called the Harry Potter gambit “brilliant.”)

Parents caught sending food disguised as necessities receive a stern call and a reminder to follow the rules.

Why would parents risk getting on the wrong side of the camp law, especially since these places typically have plenty of food options and no shortage of junk at the canteen?

Stacie Vinson, a mom of two campers at a sleep-away camp in Dubai, said she taped Airheads to the pages of books to make her 9-year-old daughter and 11-year-old son feel like they’re not away from home.

“The novels got ruined by the tape but at least the kids were happy,” said Vinson.

Wendy Siegel, an owner and director of Tyler Hill Camp in the Poconos, suspects it’s more of a cat-and-mouse game. A camper’s family once gifted their child a teddy bear on visiting day. When the counselor helped make the bed a few days later, she noticed the bear was lumpy. Upon further inspection, she discovered the stuffing had been removed, replaced with a variety of candy and resewn.

“I think there’s a sense of, ‘Ha-ha we snuck one by you and we won,’” Siegel said.

That’s how Tiffany Karsenty felt when she designed a scheme to smuggle food to her daughter in 2021 when visiting day was scrapped because of Covid. Parents were told the camp would provide treats to make up for the cancellation, but that they were free to send nonfood items. They were warned that packages would be inspected for food.

“It was my own challenge to see if I could get it through,” said Karsenty, of Cherry Hill, N.J.

She sent a decoy package with sweatshirts that contained candy in the sleeves and rolled in a towel at the bottom of the basket knowing they’d be found. The second round of contraband arrived in a separate package. She removed all the pieces and board from Monopoly and packed it with candy. She used a hair dryer to seal the box with cellophane so it looked unopened. The final piece of the deception: A note to her daughter explaining the scheme.

“I sent the mom group chat photos and they were like, ‘How did you think of this? That’s genius,’” said Karsenty.

Jessica Siegel, now 37, still remembers the joy of receiving a package during her only summer at Camp Chi in Wisconsin as a 10-year-old. She had been feeling homesick and was thrilled when a box arrived. She opened it to find towels, which was odd since she didn’t need them, but discovered Charleston Chews hidden inside.

“Even if you’re having the best time ever, knowing your family is out there and cares about you is a touch point with the outside world,” said Siegel, of Chicago.

It’s not always food. Last summer, a clicker fidget toy was all the rage at Tyler Hill. So when a parent contacted her daughter’s division leader asking to mail the face-cleansing wipes her daughter ran out of, the staff approved it. Little did the mom know, Siegel had overheard her bragging to other parents about how she planned to stuff fidget clickers under the wipes.

So when the camper opened the package in front of staff, as required, justice was swift.

“She was walking around town saying she figured out a way to sneak it in,” Siegel said of the mom. “There’s a bragging right but I got the bragging right of finding it.”

Kennybrook’s Landman recalls a camper last year who brought two burner phones into camp, so when he was caught with one, he had an extra. The joke was on him when Landman checked Instagram and discovered the camper had posted a birthday message to his mom that day.

“I’m friends with the mom on Instagram so I saw it,” Landman said. “He was busted.”