Just received from US embassy:
"The U.S. Embassy wishes to inform U.S. citizens living and traveling in Argentina that in recent months, U.S. citizens have reported a number of crimes to the embassy. Crimes reported include petty crime, taxi scams (especially at international airports), mugging, snatch-and-grab robbery involving motorcycles and bicycles, and occasionally more serious crimes such as express kidnapping, home invasion, carjacking, assault, and sexual assault using date rape drugs. We recommend that U.S. citizens traveling and living in Argentina always be aware of their surroundings, maintain a high level of vigilance, and take appropriate steps to enhance their personal security. Please consult reliable sources for information on transportation, lodging, and the general security of areas you are visiting".