Who wouldn't want to get paid to go shopping? That's partly the allure behind "mystery shopper" scams.

While they aren't new, these phony "we'll-pay-you-to-shop"-type ads sprouted like online weeds during the recession as job-hungry Americans hunted for employment.

Law enforcement and some financial institutions say they're spotting mystery shopping scam attempts, which involve phony checks deposited into a victim's bank account, several times a week.

"We've been seeing it pretty frequently since 2005," said Vanessa Oddo, finance loss prevention manager for SAFE Federal Credit Union, based in North Highlands, Calif. She said about 200 to 300 suspect checks get brought in to SAFE branches every year.

Similarly, the Northeast California Better Business Bureau office said it gets two or three calls a day asking about mystery shopper checks they've received in the mail.

"Luckily, most people call us beforehand," said BBB spokeswoman Cailin Peterson in an email. "We get maybe 10 people a year who have actually cashed the checks, though who knows how many people just put up with the loss and move on."

The losses can be anywhere from a few hundred to several thousand dollars, depending on how much was deposited into the unsuspecting shopper's bank account.

There are plenty of legitimate mystery shopping companies, which hire individuals to drop in unannounced at retailers, hotels, fast food outlets, restaurants and other businesses to secretly evaluate customer service.

But the fraudulent kind typically operate as fake check scams.

Making contact by mail, email or phone, a fraudster posing as a mystery shopping company "hires" an unsuspecting consumer, who is promised payment after completing a "first assignment." That assignment often involves sending a phony check to the consumer's home, with instructions to deposit it in a bank account, keep a small amount as reimbursement, then wire the remainder to Western Union, ostensibly to report on the wire company's "customer service."

Ultimately, the phony check bounces, leaving the victim's bank account dinged for the total amount, as well as wire transfer charges and possible bank fees.

"You see more of these during a recession, when people are searching for jobs or ways to (make) more money. Scammers plan on that," said Dan Denston, executive director of the North America Mystery Shopping Providers Association.