Before their camping trip back in May, Curtis Castro and his friends stopped in at the I.V. Deli Mart to pick up snacks. The spot is popular among students who go to the University of California, Santa Barbara.

As the rising junior wandered the aisles, he heard a loud commotion nearby but figured it wasn't a big deal.

“We thought it was fireworks,” Castro said. He and his pals left, and minutes later, a student who has since been identified as Elliot Rodger shot up the deli, leaving its windows riddled with bullet holes.

That day, the disturbed 22-year-old killed six people and wounded 13 others before committing suicide.

That Castro is still alive, he recognizes, is a matter of luck—and although he doesn't own a gun, he said he would’ve liked to have one as the tragedy unfolded.

“If I was in that deli when the guy came and shot it, I don’t know how I would react,” he said. “But I’d like to think that I would have the mental clarity and capacity to stop it."

Castro’s romantic vision of heroism is not a new one. For years, perhaps the most prevalent argument for allowing guns on campuses has been that they can be used for self-defense in an active shooter situation. The epicenter of this debate is concealed carry, the right of gun owners to carry concealed weapons in public with state permits.

On Tuesday, Idaho became the seventh state to allow carrying of concealed weapons on public college campuses, joining Colorado, Kansas, Mississippi, Oregon, Utah, and Wisconsin, according to the National Conference of State Legislatures.

The bill, drafted by the NRA and signed into law in March, was publicly opposed by all eight of Idaho’s college presidents and will allow permit holders to carry their weapons on university grounds—excluding dorms and venues with more than 1,000 people.

“I think the Second Amendment was designed to protect lives, and the strange thing about this legislation is that I think it may have the opposite effect intended by the Second Amendment,” Bob Kustra, the president of Boise State University, said in a February radio interview.

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Having armed civilians on campus could confuse law enforcement in an emergency situation, making it difficult for officers to distinguish the good guys from the bad if both have drawn weapons, Kustra has said.

Kustra is not alone. Nearly 95 percent of respondents opposed allowing concealed weapons on campus, according to a survey of more than 400 university administrators released earlier this month.

Gun advocates argue that despite this opposition from college leaders, gun control on campus is a matter of consistency.

“If the person is trusted to have a concealed firearm when they're going to, for example, a library, or the grocery store, or simply walking down the street...then we don’t understand the rational basis for excluding college campuses from that otherwise generally allowed list,” said Kurt Mueller, a spokesperson for Students for Concealed Carry on Campus.

State-given permits, Mueller added, shouldn't face limits nearly anywhere in the state, excluding high-security areas such as airports or prisons. Walmart, hospitals, college campuses: “I don’t see how it would pose more danger on college campuses than it would pose anywhere else,” said Mueller.

The problem with the argument that you need more guns to be safer is that college campuses are already pretty secure, said Andy Pelosi, president of The Campaign to Keep Guns off Campus.

Nearly 93 percent of college-student victimizations happen off-campus, dwarfing on-campus crime—7.1 percent, according to a report from Department of Justice officials who tracked college crime from 1995 to 2002.

Another issue is that college students are still maturing, still coping with the stresses of adulthood. Their college years mark the peak time for experimentation with drugs and alcohol. It can also be the first time mental illnesses such as schizophrenia are detectable: Onset for men is typically between the ages of 16 and 25; for women it's 18 and 25.

Throw a gun into the mix, Pelosi said, and there’s a possibility that will result in serious injury or death.

“Gun-owning college students are more likely than their unarmed counterparts to drink frequently and excessively and, when inebriated, to engage in activities that put themselves and others at risk for life-threatening injury, such as driving when under the influence of alcohol, vandalizing property, and having unprotected intercourse,” according to a 2002 article from the Journal of American College Health.

In addition, the article claimed, having a firearm for protection was also “strongly associated with being threatened with a gun while at college.”

Another potential for danger is through theft: Pelosi argues that dorm rooms are not nearly as secure as gun storage facilities, which can increase the potential for unintentional shootings and domestic violence or threats.

Nearly 1.7 million firearms were reported stolen to the police between 1993 and 2002, according to the Brady Campaign to Prevent Gun Violence. Furthermore, the campaign writes on its website, once a gun is stolen, it is more likely to be used in a crime.

Most stolen weapons are taken from homes and parked cars. Yet in some of the states that allow guns on campus but outline "school safety zones" where weapons cannot be carried, parked cars on school property are often exempt.

Another issue is the potential for accidental shootings or misfires; 91 percent of university presidents surveyed said that that was the greatest disadvantage of allowing concealed firearms on campus. Students aren't thrilled about the idea of guns on campus either—a 2013 report found that 78 percent of students at 15 Midwestern colleges don't want firearms at school.

Accidental shootings occur 40 to 50 times daily, adding up to 19,000 unintentional shootings a year, according to the Centers for Disease Control and Prevention.

However, Mueller said Utah, which is typically viewed as a success story for concealed carry, provides evidence that “concealed-carry firearm violence doesn’t happen” in general.

In late February, officials from universities in Utah told watchdog publication IdahoReporter.com that allowing guns on campus hadn’t caused any problems in the years following the policy’s implementation in 2007.

One public safety official from Utah’s Dixie State College confirmed that there hadn’t been any accidental shootings on campus—but there still have been problems.

These include reports of students threatening or intimating gun violence and students accidentally dropping their weapons. In one incident, a library patron sat on a gun that had accidentally been left on a chair and, not realizing it was real, proceeded to play with it.

“I’m surprised she didn’t start shooting that thing, thinking it was a fake,” the Dixie State official told IdahoReporter.com.

Castro, the UCSB student, understands the dangers of real guns in real students' hands.

“I knew that there had been victims but not who died until the next morning,” Castro said of the Isla Vista shooting. “I knew three of the girls that got shot.”

Of the three, one survived.

Though Castro would have liked to be armed had he encountered Rodger, he finds the idea of having more guns on campus unsettling—in large part because despite the extra hurdles required to get a concealed-carry permit, he believes that it is still too easy to do so.

“I don’t think it would be safe,” Castro said.