A Smiths Falls, Ont., retailer has turned to social media to warn customers that it had been hit by a scam involving popular prepaid gift cards that have been tampered with.

The Shoppers Drug Mart on Beckwith Street posted a photo of Starbucks gift cards with stickers placed over the bar code.

"They place a thin sticker with a new barcode across the back of the cards so when we try to sell these particular Starbucks cards it comes up as a Best Buy card," said Tracey Merkley, the store's assistant manager.

They're just sitting at home, checking balances ... and then they have the money - Tracey Merkley, Shoppers Drug Mart

"They're just sitting at home, checking balances, waiting for us to activate [the cards], and then they have the money."

Merkley said she was warned about the fraudulent cards by the retailer's Perth, Ont., location.

"We just didn't use to think we had to worry about the small store cards because [the scammers] wanted access to fast cash," she said.

"That's why they liked the Visas, and now they've found a way to put them toward the store they want, which is Best Buy in this case."

Merkley said the store hasn't received any complaints from customers who bought worthless Starbucks cards, but said the retailer has taken precautions nonetheless.

Warning for other retailers

Smiths Falls police are applauding the retailer for sounding the alarm about the tampering.

Const. Aaron Tompkins said it can be difficult to confirm where in the supply chain the tampering occurred.

"There's no way to definitively say there was a person at the gift card rack and we saw him or her replacing stickers or putting stickers on," Tompkins said. "There's not much of an electronic trail from these activations."

Tompkins said police are educating stores about different ways gift cards are used by fraudsters.

"Likely, it wasn't just the one or two stores," Tompkins said.

Gift cards a 'hot commodity'

The Canadian Anti-Fraud Centre (CAFC) said it has received some reports of organized retail thefts targeting gift cards.

Jeff Thomson, senior RCMP analyst at the CAFC, said criminal groups will often target a series of retailers as they travel through an area before moving on.

Jeff Thomson, a senior RCMP intelligence analyst with the Canadian Anti-Fraud Centre, says gift cards are a 'hot commodity' among scammers. (Jean Delisle/CBC)

Thomson said cards are "a hot commodity for fraudsters" because they allow them to cash out anonymously.

Merkley said staff at her Shoppers Drug Mart has been trained to double-check the cards and receipts to ensure the money goes to the intended recipient, but customers need to be aware as well.