Flower Mound police say a door-to-door sales scheme is designed to look like a missed delivery.
Residents have received small slips on their doors that say "Sorry we missed you" and have "first attempt" box checked and a phone number to call for more information.
Flower Mound police Capt. Wess Griffin said it is "an adhesive notice similar to what you would see from UPS or FedEx."
"When you call the number and give the reference number, it's a sales pitch," he said.
Griffin said this is the first time he has seen the marketing scheme, but a Web search revealed that it has happened in other cities across the country.
"It's, maybe, not scrupulous, but it's not illegal either," Griffin said.
Like door-hanger advertisements, such slips are protected by interstate commerce, he said.
A Flower Mound ordinance requires door-to-door salespeople to register with the town and get a special photo ID.
The police department's citizens academy alumni recently began giving out specially made "no solicitors" signs to curb the issue
But the ads remain legal and are a common sight.
"It's like every day, there's something out here, practically -- every day, on the door hanging," Bob Williams said.
Leslie Hargus said she gets the them at least two or three times a week.
"I don't even look at them," she said. "Usually, my kids bring them in and, yeah, they end up in the garbage."
While legal, police urge caution, saying the advertisements can open the door to problems.
"You want to do some small things just to make sure you don't become a victim of crime," Griffin said.
He advises people to never give out any personal information to solicitors and to always look into the company before agreeing to anything.
It's also not a bad idea to alert everyone in your household if you are actually expecting a package, he said.
Flower Mound police also remind people to remove the advertisements from their doors as soon as possible or have a neighbor do so if you are out of town. Otherwise, they can signal to would-be criminals that no one is home.
"If you ever have a question or are suspicious about a circumstance like that, be sure to call your non-emergency police number and let us check it out," Griffin said.