Travel is one of the world's largest industries, and it is expanding exponentially. Unfortunately, scamming is also a growth industry that you may encounter before your departure as well as while you're traveling. In this column, I'll address scams in the field and reserve white-collar travel fraud as a future topic.

Each new tourist season provides a fresh crop of inexperienced travelers at the mercy of ripoff artists. Veteran globetrotters will advise you, most importantly, to be aware of your surroundings — to be streetwise. And they recommend that you ask your hotel concierge, cab driver, tour guide and fellow travelers what particular swindles are being perpetrated locally.

The following are classic scams to guard against while traveling:

THE STAIN TRICK

In a crowd, a person eating a hotdog will brush against you, leaving a blob of mustard or ketchup on your clothes. He will apologize profusely, and frantically try to remove the stain. Meanwhile, his partner has pilfered the luggage you put down, or picked your pockets. If someone starts cleaning a stain on you, aggressively hold onto your belongings, retreat, and clean yourself off in a less-crowded spot.

THE BUMP DUMP

Again, the fraudsters use physical contact. One thief will bump into you hard enough to knock you into his partner, who falls to the ground. While you and the fallen partner are scrambling to get up, the first thief pretends to help while rifling your pockets or handbag. Always suspect hanky-panky when strangers bump you. Hold onto your valuables and move away as quickly as possible.

THE METAL DETECTOR HUSTLE

Thieves working in pairs watch for targets approaching airport metal detectors and are especially fond of those carrying laptop computers. One thief waits until the victim places his bag on the conveyor belt through the X-ray machine, then cuts in line in front of the victim and sets off the metal detector, causing a delay and distraction. Meanwhile, the thief's partner, waiting on the other side of the metal detector, snatches the victim's bag and disappears among the crowds. To defend against this trick, travel in pairs. One friend should pass through the detector two places ahead so that he can collect all of the carry-on bags.

PICKPOCKET WITH NEWSPAPER

A man pretending to read a newspaper bumps into you. As he makes a big deal of apologizing, he uses the newspaper to shield your view from his picking your pockets or handbag. Be suspicious of any stranger who enters your personal space. Hold onto your wallet or bag, and move quickly away.

THE SANDWICH

As you try to disembark from a crowded subway or train, someone getting on will bump into you. He pushes you into his partner behind you who will pick your pocket while you are flustered. Be on guard: keep your hands over your valuables and don't let bumps and jostling deter you. If you feel a hand in your pocket, grab it if you can and yell "Thief!" The English word is understood almost everywhere.

MOBBED AND ROBBED

Especially popular in Rome, a horde of children run up to a tourist, asking for change or a photo. As the kids tug on their intended victim, begging and pleading, several more stand behind, rummaging through packs and pockets. The well-trained children often choose targets that cannot easily flee such as infirm elders and pregnant women. Keep yelling for help as you move away from the little thieves.

FAKE ROAD ACCIDENT

A group of thieves creates a fake roadside accident, usually on a rural highway and often involving at least one "victim" sprawled out in the road, blocking your path. When the Good Samaritan stops and gets out of his car to see if he can help, he is robbed of his possessions, his car and perhaps his life. This is a very dangerous scam. Trust your instincts. If this happens to you, try driving around the victim, slowly and determinedly, but leaving no doubt that you will not stop, even if people put themselves in your way.

RENTAL-CAR BREAK-INS

Thieves in tourist areas know that rental cars are often full of cameras and luggage. Your defense is to minimize the chances of your car being a target. If there is a rental company sticker or license plate frame on the car, remove them. Do not leave signs of your tourist status, such as maps or luggage, visible in the car when you park it. And ask at your hotel where the safest places are to park at your destination.

Irene Croft Jr. of Kailua, Kona, is a travel writer and 40-year veteran globetrotter. Her column is published in this section every other week.