AN image of a bag screened by the Transportation Security Administration,
Guns are prohibited in carry-on baggage. The person who tried to get this gun through an airport security checkpoint got stopped, and got in trouble. Courtesy of the Transportation Security Administration

Gun-free zones are a favorite target for gun fanatics. They love to point out, again and again, that just saying a place is gun-free will not stop a mass shooter. What's needed to make a bad guy with a gun think twice, they argue, are good guys with guns. A good example of this kind of rationalization can be found in this National Review post.

Here, the right is right: Gun-free zones are pretty stupid. We should not even bother with them. No one who has it in their mind to pop people before popping themselves is going to notice, let alone be dissuaded by, a sign that says you're in a gun-free zone. Those are just words on a wall.

But what would happen if a gun-free zone was rigorously, actively, physically enforced? Would it have more substance than mere words? Would it be effective?

All we need to do to answer these questions is to look at airports.

Though you are allowed to travel with a firearm, it has to be in your checked luggage, and there are regulations about how your gun and your ammo has to be packed.

Lorie Dankers, the regional spokesperson for Transportation Security Administration, explained to me over the phone that because many people are unaware that the areas beyond security checkpoints are enforced gun-free zones, loaded firearms are frequently spotted during screenings. When the discovery of a loaded firearm is made in the screening line at an airport, as happened in the image at the top of this post, it shuts down the whole process. Nothing moves. People wait and wait and miss planes. TSA officials are not armed, but armed officers eventually arrive and take away the owner of the firearm. He/she might face huge fines.

By the way, in 2015, the airports with the most firearm discoveries during security checkpoints were:

Dallas/Fort Worth International Airport: 153
Hartsfield-Jackson Atlanta International Airport: 144
Houston George Bush Intercontinental Airport: 100

Seattle had 59 firearm discoveries in 2015, and so ranked 7th in the nation, Dankers explained. The terminals at Sea-Tac past the security checkpoints, like the terminals past security checkpoints at airports nation-wide, are real gun-free zones.

When I asked Dankers if there had ever been a mass shooting in one of these secure areas, she said: "I have never heard of one, not in my time on this job."

The Port of Seattle's Peter McGraw, who is handling media relations for Sea-Tac while someone is on vacation, explained that he too had never heard of a mass shooting or any kind of shooting inside of Sea-Tac. I emailed and called the national office for TSA to see if they had a record of a mass shooting in an airport, but they have not gotten back to me.

A Google search recalled only the shooting that happened at an LAX checkpoint in 2013. The killer entered the secure area after shooting to death a TSA officer. But he was soon cornered, shot several times, and arrested, so I don't think we can call that a "mass shooting."

The inquiry on the LAX shooting revealed several lapses in security procedures and emergency coordination. There was some talk of arming TSA officers, but this idea was wisely dropped. The fewer guns in an airport, the better. As Tom Ridge, the former secretary for the United States Department of Homeland Security, explained, arming TSA officers would be a "big mistake." As he pointed out, we already "have literally hundreds and hundreds of armed police officers roaming every major airport in America. And I don't think arming another 40 or 50 or 60 thousand people... would have prevented this incident from happening."

So, the kind of thing that happened yesterday at the Renton movie theater (a woman was shot while watching Michael Bay’s new Benghazi movie, 13 Hours) appears to never happen in gun-free zones that enforce their words.