Whether you prefer Do-Si-Dos or Thin Mints, almost everyone loves a Girl Scout cookie, but the annual fundraiser has created a spike in crime across the country this year that has even the Secret Service stepping in.

At least two troops on opposite sides of the U.S. have received counterfeit money in exchange for boxes of their cookies. Troop 60916 in Tynsborough, Mass., spent Sunday afternoon selling cookies, and took their $258 deposit to the bank when the teller told troop leader Dianna Mines that four of her $20 bills were fake.

But the Massachusetts troop wasn't the only one hit by counterfeiters. Scouts in the Central California South council based in Fresno, Calif., received a fake $100 bill in exchange for cookies, and their council store received two more.

"Sometimes you think $100 isn't a big deal, but, for that little girl selling cookies for hours or the volunteer giving their time, it's a lot," said Cathy Ferguson, CEO of the Girl Scouts of Central California South.

That's when the Secret Service stepped in, thanks to a troop dad who works with the agency. Agents conducted a workshop that taught staff members and troop leaders how to recognize phony money. They were told to look for three key signs: a watermark portrait to the right of the printed president's picture, a security strip on the left imprinted with the letters "USA" and the amount of the bill, and color-shifting numbers that can be detected when the bill is held at an angle in the light.

Ferguson said the money from the cookie sales stays within each individual troop to fund their programs so they are the ones that benefit from the hands-on training.

"It's not like they're taking money from the Girl Scouts of America. That little girl standing there with a smile on her face is the one they're ripping off," Ferguson said.

To read the complete article, see:After Fake Bills Passed, Girl Scouts Get Schooled By Secret Service(abcnews.go.com/US/california-girl-scouts-lesson-secret
-service-receiving-counterfeit/story?id=15928039#.T2TykRGPU4Q)