LAS VEGAS (AP) -- At the same time President Barack Obama was unveiling plans to combat gun violence on Wednesday, about 120 attendees at the annual Shooting, Hunting and Outdoor Trade Show in Las Vegas were attending a seminar about identifying people who shouldn't be buying weapons.

Greg Rose, a gun store worker from Ann Arbor., Mich., emerged from the hour-long session headed by a federal Bureau of Alcohol, Tobacco, Firearms and Explosives supervisor saying that he thinks most licensed sellers ask themselves if someone trying to buy a gun should be buying a gun.

"I think the majority of retailers out there really do look at people and ask if it's warranted," Rose said. He recalled asking a woman in her 60s who wanted to buy a handgun to first take a weapon safety class. He said she did, and he sold her the gun.

Thomas Chittum III, the top ATF agent in Las Vegas, said the kind of care Rose described is what he tries to teach in his "Detecting and Avoiding Straw Purchases" class. Straw buyers are people who illegally buy a firearm on behalf of a person who is prohibited from doing so.

"Dealers are under no obligation to sell a firearm to someone they are not comfortable selling it to," Chittum said. "That's what I preach — to trust their instincts. If they don't feel right about it, don't sell it."

People who can't own guns include convicted felons, people convicted of misdemeanor domestic violence or named in a domestic violence restraining order, fugitives, illegal drug users, illegal immigrants and people who have been found mentally defective or who have been involuntarily committed to a mental hospital.

Chittum's seminar was one of three hosted by the ATF on Wednesday and 20 offered during the four days of the annual SHOT Show for some 60,000 industry professionals, recreational gun owners and law enforcers at the Sands Expo Convention Center on the Las Vegas Strip. The event is closed to the public.

Bill Brassard Jr., spokesman for the National Shooting Sports Foundation hosting the convention, said the seminars aim to share the latest industry regulations and guidelines with show attendees. The NSSF also hosted several hundred retailers the day before the convention for a day of classes and business tips, dubbed SHOT Show University.

Yet even as conventioneers studied on Wednesday, some rules in the gun world were changing.

Obama invoked the memory of 20 schoolchildren and six adults killed a month ago by a gunman at a Connecticut school in his call for background checks for all gun sales and a ban on military-style assault weapons and high-capacity ammunition magazines.

The president avoided certain opposition from the powerful National Rifle Association and its allies by signing 23 executive actions, including orders to make more federal data available for background checks and to end a freeze on government research on gun violence. Congressional approval will be needed for more robust changes.

"It'll be interesting to see what passes," Rose said, adding that he hadn't heard a lot of talk about the president's plan during his tour of the miles of aisles of vendor displays at the convention. "In one sense people are pushing back saying it's an affront to freedom."

Rose said he has never been opposed to universal background checks.

"How you implement it is another issue," he said. "For the retailer, it's actually beneficial because people will have to come into the store to register the sale of the firearm. You get them in the store they'll want to buy other things."

The National Shooting Sports Foundation issued a statement at the Las Vegas show calling it critical to keep firearms out of the hands of people it calls irresponsible and not legally qualified to possess them.

"We believe the personal responsibility of gun owners, especially if there are children or at-risk individuals in the home, is central to any meaningful discussion of the issues," the statement said.

Associated Press photographer Julie Jacobson contributed to this report.