What's worse than waiting for your food to be delivered? How about if it never shows up? Now, some of those flyers under your door are more than just annoying. They could be helping crooks pull off a... See More
What's worse than waiting for your food to be delivered? How about if it never shows up? Now, some of those flyers under your door are more than just annoying. They could be helping crooks pull off a fast food fast one. And that's not the only way clever scammers can come after your money. So before you head off for that last summer holiday, how can you protect yourself from those seriously sneaky schemes? Here's ABC's linsey Davis. One of my favorite restaurants. Reporter: It began as a fun trip for this mother-daughter duo. But for Chris and Katie they stay at their New Orleans hotel turned into a nightmare. It's about midnight. And our hotel room phone rings. And it's one of the ladies from the front desk. Explaining, I need your card number to put on file, otherwise, you need to get out of the room. And I was like, oh, my. Okay, this lady's serious. I gave her my card number. And -- and that was that. Reporter: So satekatie gave her card number and went back to sleep. The next morning -- I woke up and thought to myself, there's something sketchy about that call. She checks her bank account and realizes all her money is gone. Reporter: Turns out it wasn't the hotel front desk. Katie had given her information to a scammer and this particular scam is so common, many hotels, including the one Chris and Katie stayed at, post warnings about it. The American hotel and lodging industry says it provides regular updates to hoteliers on scammers targeting hotel guests. Like this one, the pizza scam. You'll find flyers under your door when you check into the hotel. You call, you give them your credit card information, you order your pizza. Nothing comes. Because they're really not a restaura restaurant? It's nothing, it's a thief. There's the wi-fi scam. That's where you, in your hotel, you're searching for a wi-fi system, you find the system you think is the hotel's wi-fi system. But it isn't. Be very careful with the kind of information that you provide. And the kind of things that you do. Stay away from banking transactions. Maybe don't look at your e-mail. Reporter: In a statement to ABC news, a representative from the St. Christopher hotel writes "Every guest who checks into our hotel is given a credit card scam letter making the guest aware of the scam and advising the guest not to divulge any credit card or other sensitive information." But they say they didn't see the warning letter until it was too late. And it's not just at hotels where you can fall victim to these kinds of scams. As millions of Americans hit the road next week for the labor day weekend, thieves are also preying on atm machines and gas stations with a practice called skimming. I knew it was stealing, I knew it was wrong. Reporter: Dan is a reformed credit card hacker who got busted and switched sides to avoid prison time. I was printing my own fake credit cards. I would go to the store, purchase electronics, I would resell them. Reporter: He spent two years training agents in the dark arts of skimming. He spoke to my colleague nick watt. The atm cashing was the easiest way. I was making thousands a day in cash doing that. Reporter: His favorite target, gas stations. Installing gadgets like this one inside the pumps. Gas station skimming is one of the easiest and best ways of doing it. It's hidden, the person using it will never see it, it takes seconds to open it up and put it in there. This is a reader that would be inside the gas pump. You would swipe it through and it would read it right here. Nobody would know the difference. Reporter: When investigators at the Arizona department of weights and measures -- We're checking for skimming devices. Reporter: -- Found a skimmer inside this gas pump, they decided it was time to fight fire with fire. We inserted one of these little night vision spy cams in the back of the dispenser. Reporter: And bingo. Here's the view from that camera inside. Apparently showing a man and woman team caught red handed. What we have here action we have the guy. It's awesome. Reporter: They start bickering when they can't find any of their devices. So it's almost like a husband and wife team arguing about where their skimmer is, because somebody got it. That was us, we got it. Reporter: Law enforcement is still on the hunt for Mr. And Mrs. Skimmer. But in the meantime, there are some things you can and should do to protect your digits. Rule number one, never give credit card information over the phone once you've checked into a room. Go to the front desk. You want to see the person who is getting this information from you. I tell family members, friends, don't say anything over the telephone. Reporter: Number two, check in with a credit card instead of a debit card. They can move that money out of your bank account in the blink of an eye. Reporter: If you're fueling up, choose the pump near the attendant, crooks prefer to operate in the shadows. Or pay in cash. Lastly, no matter where you are, check your account. A lot. Most companies will erase any fraudulent charges on your credit card if you report them within 60 days. The best places, the most secure locations, things like this can potentially happen. Reporter: The mother and daughter, they say their trip was ruined. We were especially embarrassed because we consider ourselves savvy to that sort of thing. You know. We couldn't possibly be scammed. Like we would fall for that. Reporter: The advice we heard action it's fine to let your hair down on vacation but don't let down your guard. Nor for "Nightline," I'm linsey Davis in New York.
This transcript has been automatically generated and may not be 100% accurate.