Where you're getting kidnapped: Anywhere, really, but it’s most common in border cities like Juarez, Tijuana, and Tampico.
Who’s getting kidnapped: Mexico is a fairly equal-opportunity country when it comes to stealing people, though the more-publicized and brutal incidents mostly involve locals, not tourists.
Who’s doing the kidnapping: Unless you’re an international drug mule (or a guy in an RV with Jennifer Aniston pretending to be one), the cartels will likely leave you alone. It’s the random street thugs and rogue cab drivers that you should worry about.
How they're kidnapping you: The majority of American kidnappings in Mexico involve ATM holdups, where tourists are kept for a few days while they withdraw as much money as possible. "Express kidnappings” can be common as well, and involve being held until a family member pays a ransom. So be sure to buy everyone nice presents before you leave.