But they claim police are trespassing by wiping door handles with a cloth that collects traces of illegal drugs.
The men, in separate cases, are challenging the use of test results that allegedly revealed microscopic drug particles on their front doors - information officers used to bolster their requests for search warrants.
To the trio, the high-tech approach is a blatant violation of the Fourth Amendment right to be free of unreasonable searches.
A person has a subjective expectation of privacy in their front door, which is part of the home itself, assistant federal defender Wendy Lewis wrote in her request to throw out evidence seized during a 2003 search of Anthony Diviase Mora's house in Ogden.
Although we may allow for someone knocking on the door, we do expect that items on the front door themselves are protected, she said.
But federal prosecutors insist no warrant is needed to swab a doorknob and run the test - called an Ionscan - to detect whether occupants and visitors have been in contact with drugs. The exterior of a home cannot be expected to remain untouched, they say, as friends, solicitors, proselytizers, campaign workers and delivery people come to the door.
Assistant U.S. Attorney Leshia Lee-Dixon pointed out that visitors to Mora's home were directed by a sign to go around to the back door. The invitation meant officers could touch the door, she wrote in a court filing.
Mora did not have a reasonable expectation of privacy in the door handles to his screen or inside back doors, Lee-Dixon wrote.
In an Ionscan, a sample is taken by rubbing a sterile cloth over a surface to collect residue. The swab is placed in a machine that analyzes particles and gives an alert when certain substances are found, such as cocaine and methamphetamine.
The technology is used at airports, including Salt Lake City's International Airport, to check suitcases for explosives.
Defense attorneys contend police using the mass spectrometry technology at a home must get a warrant first, by showing a judge other, independent evidence of illegal narcotics or firearms.
Lawyer Jon Williams, who is representing Troy Miller of South Salt Lake city, said in a brief that the front door is protected from unreasonable searches. He added: "The doorknob is the most sacrosanct part of the [home]. Its sole purpose is to gain entry."
Utah appears to be at the forefront of the legal debate, with at least three pending Ionscan challenges in U.S. District Court in Salt Lake City:
l Mora was arrested by Ogden police in December after officers allegedly found a box of bullets in his home. He is awaiting trial on a charge of possession of ammunition by a convicted felon.
l Dennis Daybell, 51, of Magna, is charged with possession of methamphetamine with intent to distribute and illegal firearm possession. Police searched his home in April.
l Miller, 33, is facing five counts of possession of controlled substances and aiding in the manufacture and sale of methamphetamine. His home was searched in March.
The cases all request that evidence from the homes be tossed out because police used the results of Ionscan tests, among other factors, to get warrants.
The only appellate ruling in such a case is from the Virgin Islands. In 1999, a trial judge threw out the analysis of a swab taken from a home's screen door, saying the search of the doorknob for marijuana residue violated the Fourth Amendment.
Appellate judges decided the case on other grounds, without examining the test.
In Utah, Judge Ted Stewart took a similar stand, ruling in August that the Ionscan test of Mora's doorknob required a warrant. He cited a 2001 U.S. Supreme Court opinion that required Oregon police to get a warrant before using thermal imaging technology, which senses the use of heat lamps.
With evidence of heat coming off the walls and the roof of a house, the officer obtained a search warrant and arrested the occupant on charges of growing marijuana. Taking the sample from Mora's door was similar, Stewart wrote. "The swab of the outside of the doorknob reveals something about the details of the interior of the home that is unknowable without physical intrusion - that persons who have handled drugs have entered," the judge said.
However, he upheld the warrant to search Mora's home, saying other evidence provided probable cause.
But his colleague, Judge Tena Campbell, said the Ionscan test differs from thermal imaging and reveals nothing about the inside of a house.
"Rather, use of the Ionscan machine is analogous to use of a trained dog to sniff and indicate the presence of narcotics," she wrote in July, refusing to throw out the evidence against Daybell.
Miller's challenge is pending before Judge Dale Kimball.
The American Civil Liberties Union of Utah considers such tests problematic when used in prisons or schools, according to executive director Dani Eyer. She said some penal institutions test the hands of all visitors, even if there is no reason to suspect they might have tried to smuggle in drugs.
"Our question was what happens when it's positive. Is due process available?" Eyer asked.
She also worries about false positives, saying poppy seeds, chlorine diaper wipes and medicines have been incorrectly analyzed as illegal substances.
However, Todd Wheeler, a special agent for the Drug Enforcement Agency and a former chemist, described the tests as "presumptive," giving law enforcement a preliminary indication of drugs. After an Ionscan returns a positive reading, other tests are conducted to confirm the substance, he said.