License to Steal -- an in-depth study of the criminal element of the Romani population, a highly organized, secretive empire known as the Gypsy Mafia -- is based on true stories taken from police records, historical data and heart-breaking interviews with victims of various scams. Gypsy Mafia games include burglary, home-improvement rip-offs, fortune-telling, shoplifting, pickpocketing and insurance and credit-card fraud.
This is an old, but still useful books on how gypsy groups, Irish & Scottish Travelers have regularly scammed and burgled thousands of victims. You can get a decent overview of the warnings from this article http://www.policemag.com/channel/gang...