Typical scenario: You’re happily dozing along on a Caribbean cruise when your smartphone buzzes you awake. It’s a frantic call from your teen grandson, and in a fuzzy, faraway voice, he says he’s on a pay phone and begs you to send electronic funds through your credit card. The story is that he’s been arrested in Cabo San Lucas on a marijuana charge. He must pay $5,000 immediately or face years in a Mexican prison.

Chances are nearly 100% that you are being scammed. According to the Federal Trade Commission, over just the past several years, more than 40,000 cases of so-called grandparent scams have been registered, and probably many others not reported. The losses are reported to be as much as $40 million!

The process starts when the credit card thieves continuously make phone calls using the same routine. When a worried grandparent believes the story is true, the urgent need for money is pitched. There are ways to avoid the grandparent scam:

1. The call is designed to shock, frighten and upset you. Stay calm and respond with ways to determine authenticity.

2. The caller obviously muffles the voice so you won’t be sure who it is, and tries to rush you to make the transaction. Without being overtly suspicious, calmly ask questions, such as where the grandchild went to school, names of other family members and home address.

3. Ask the alleged grandchild for the phone number of the nearest American consulate or embassy, so a representative can contact the local police supposedly involved with the arrest.

4. Say you need to need time to find your credit card and request that the alleged grandchild call back a few minutes later. Make a quick call to the family to determine if the grandchild is actually traveling in that area.

Of course, there’s always the chance the call is authentic, and your grandchild really needs help. However, take sensible steps to determine the truth before becoming the victim of a vicious crime.

For a recent grandparent scam incident that cost TV actress Pat Crowley $2,000, read www.latimes.com/business/la-fi-lazarus-20140902-column