Watch: Investigation: Some Home Alarm Salesmen Accused of Underhanded Tactics

Transcript for Investigation: Some Home Alarm Salesmen Accused of Underhanded Tactics

Reporter: A quiet neighborhood on the north side of Chicago. And on this day, a stranger comes knocking, a door to door salesman. What the salesman does not know, inside, the house is rigged with hidden cameras, part of a "20/20" investigation into the hard sale tactics of door to door sales of home alarm systems. The door to door sales is fraught with problems and this industry has enormous problems. Windchill watch this video of a training video. His name is Adam Shantz. He is says everyone is fair game, even those with signs that say no solasoliciting. . Why? They are easy, he says. Among the top closers, this man, Jake Dahl. He is considered so good, he has taught training classes for several companies. One of them caught on this tape obtained by "20/20." Using a trainee as a straight man as he acts out how to first get in the door. Starting out with a lie who he works for. And this man used to work with Hahl. They can trick you out and change your mind. He is coming forward on "20/20" after a falling out. To reveal what he calls the hard sale tactics by the sales people who give the industry a bad name stlanchts adp. I knock here for sure. Start with homes that have alarm systems by big companies like ADT. If it's older sign, it's a juicy sign. To find out when the system was with installed and pretend to be from ADT or GE. It's a target there. It's called the take over for swimp over. I saw you using one of our systems from ADT. Reporter: As taught by this master salesman, the customer is led to believe it's just an upgrade of an existing ADT system with new monitoring equipment. Wait, so I'm switching companies, right? It's just a monitoring company. Reporter: No. In fact, it would be an entirely new company with a five year contract. I'll do it for free. Reporter: Not free at all. The total cost could be about $3,000 over five years. ADT is suing the company. But atd, the biggest of the home security systems, says thousands have been stolen away. This is the worst we have seen this year. Lying and swindling people into switching, unknowingly switching their monitoring company. Reporter: ADT's general counsel David bleisch says his company too uses door to door sales people. But he is going after those who lie and cheat. He paid Ben Kirk $2,500 for this video. It was a real eye-opener when I saw it. That man from Florida. He said, we are upgrading the key pads. And it sounded like he was ADT. Reporter: He says when he realized he was signing a five-year contract, it was not ADT and he didn't raise the issue for several weeks. It felt like I had been had. They said there was no effort toment mislead him. And vision settled for more than $2 million and blamed any problems on rogue sales people. When we showed up, the bosses and the sales people accuse offed on deception was nowhere to be found. But there was a sign that it was accredited by the better business the bureau. And the companies that have "D" or "F" grades. You should be honest, you are going to people's door. And in big city us, any trick of the trade to get in the door is the use of scare tactics. Due to an increase in burglaries in the area, ADT will be giving you a free home security system. It sounded like a good offer. But it wasn't. That is not ADT. That is not the ADT district sign. And the people doing it picked the wrong home to target. The home of our consumer reporter E the ABC news fixer Stephanie Zimmerman and we set up hidden cam troops catch it on tape. There is one hidden ahead and one in a shopping back and one is leer in a water bottle. Once the ADT sales person arrived, Robert hall. He announced he is not from ADT. So what about the phone calls saying ADT does womaning to the door. He said that call was someone else. ADT will be giving you a free ADT home security alarm system. Are you guys ADT? No I'm not ADT. Then he said he can provide an ADT system if he wanted. If you want that, question do that for you. ADT says he is not a dealer could not offer the system. How you doing? Brian Ross, ABC news, "20/20." We are doinging a story about people like yourself. This woman was contacted on behalf of ADT. You would V just told her you can an ADT system. Would you please allow me to answer the question? Are you an ADT dealer? Can I finish what I'm saying. Can I get a drink of water. I'm having a little trouble speaking. Turns that he owns his own home security. Choice home protection. He says he has a friend who is an ADT dealer, giving Zimmerman's name. Sharing leads. It's possible from leads to be transferred from one company to another. It's pretty standard. ADT says that is not supposed to happen and fired the dealer who shared the names from pro vided by hall. Hall says he is a victim of acts of others. Whoever is responsible for getting him in the door, the tackics did Flot work on this day.

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Watch: Investigation: Some Home Alarm Salesmen Accused of Underhanded Tactics