Airports and airlines are reducing baggage-carousel security to save money, increasing the risk for theft. Thieves often can simply take a bag off the carousel and walk out of the airport without having to prove to anyone that the bag is theirs.

In the past, air travelers typically had to show a security guard a luggage ticket to prove that they owned the bags they took from the carousel.

Most thieves are not caught—and victims have no way of knowing that their luggage was stolen and not just lost by the airline. But recent arrests of large-scale luggage thieves in Miami and ­Chicago hint at the scale of the problem.

What to do: If you must check a bag, get to the carousel as soon as possible after landing—it’s a poor time for a bathroom stop. Position yourself as close as possible to the ramp or chute where luggage enters the carousel. Purchase distinctive-looking luggage, or put distinctive tags or tape on your bags. Thieves generally shy away from distinctive bags because they can’t claim they thought the bag was theirs if they are stopped…and it makes them easy to spot if security camera footage is later reviewed. Avoid checking high-end bags if possible—thieves target these because they often contain expensive goods.

If your luggage does disappear, contact the issuer of the credit card you used to book the trip as well as the airline. Many credit cards now cover luggage losses above reimbursement limits imposed by airlines.

Do not pack jewelry, cash, antiques or electronics in checked bags, because these often are not covered by airline and credit card reimbursement programs.