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Moments after Monday night's terror attack at an Ariana Grande concert in England, multiple concertgoers were taking to Twitter to suggest that security at the venue could have been tighter.

True or not, the claim is already prompting some serious rethinking of security measures at venues across the world, especially as the summer season, typically filled with concerts and other large-scale events, approaches.

"SECURITY IS NOT GOOD AT MANCHESTER ARENA NO ONE WAS CHECKING OUR BAGS OR JACKETS OR ANYTHING!!!" one person tweeted.

Another Twitter user, who was apparently at the concert, suggested they were "not surprised someone was able to take something into the arena. Security was horrendous."

Dawn Waddy, a woman who attended the concert with her daughter and a friend, told Sky News that security "never checked bags at all, I never saw them check anybody's bags." Waddy claims she was even scolded by security after telling them that a woman sitting near her was acting suspiciously.

In response to the claims from Waddy and others, Fox received a statement attributable to SMG, which manages Manchester Arena, suggesting "[w]hile we do not comment on our specific security protocols, we will continue to work - as always - with law enforcement officials to ensure the safety and security of our guests, both inside and outside of our facility." In a statement on Twitter, Arena officials pointed out that "[t]he incident took place outside the venue in a public space."

Nonetheless, experts agree that security procedures at similar venues around the world are likely to be stepped-up as a result of the carnage.

Experts says you can expect visible changes this summer -- but don't give in to fear

Stuart Varney of the Fox Business Network writes that "this is the start of the concert season," and he believes that not only was the Manchester attack "surely timed to make people think twice about being in crowds," he believes it was likely "designed to instill terror in parents and families as summer begins."

Already, officials in London are announcing that there will be more police on the streets, and the U.S. Department of Homeland Security is warning that "the public may experience increased security in and around public places and events as officials take additional precautions." The New York Police Department is deploying additional “heavy weapons teams” and specialized K-9 units, and warning of increased bag checks at transit hubs.

Manchester terror attack suspect identified as Salman Abedi

Madison Square Garden, the New York City venue of nearly equal-size to the Manchester Arena, is also reportedly increasing its security measures and police presence. In the wake of the November 2015, attack on the Bataclan concert hall in Paris, promotion behemoths Live Nation and A.E.G. both announced they would be stepping up security, though they declined to elaborate on the specifics.

Michael Balboni, the former New York state Homeland Security director who helped advise on security for the rebuilding of the World Trade Center, suggests these kinds of changes can be good, but it's the will of the people to persevere that is most important.

"We're always reactive to these events, like the Times Square incident last week with the car," Balboni said. "All of a sudden the next day, even though this was essentially an incident that had nothing to do with a terror nexus, you still see the police patrols out in the street with vests and heavy weapons... that’s what they thought people would need.”

But, Balboni added, though people should be vigilant they need to “recognize that this should not be changing their lives."

Striking a balance between security and personal liberty

Balboni suggests two key changes are necessary when it comes to current security procedures: Increasing the distance between the security perimeter and the venue itself, and making sure that security personnel remain on guard as people leave the event.

"This is about not stopping security until the event is over and people are on their way home," Balboni said, something that he admits will mean "more resources" for both security and law enforcement.

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When it comes to the perimeter, Balboni argues that "the further out you have the security cordon, the more dispersed people are, the less body count you'll have, and also you'll have more time to spot a potential attacker."

According to Balboni, "the question then becomes, for law enforcement at any of these venues, how far out do you check people? What’s reasonable?”

Former Boston Police Commissioner Ed Davis told Fox Business Network's Maria Bartiromo that "we clearly will have to increase security at concerts now," though he adds that extending the perimeter often creates a new set of problems.

"No matter where you put the security perimeter,” Davis said, “there's going to be a line that forms and when that line forms it's subject to attack."

Balboni said there is no way to eliminate the risk, but it can be managed. Still, he admits, "there is nothing you can do to stop a lone wolf suicide bomber from walking into a crowd of people.”

“I learned that from actually training with the New York State Police and NYPD as they conducted drills using handguns. How fast you have to react, how it happens in a split-second and you can’t be wrong. You can't shoot an innocent person just because you think they’re acting suspiciously, and the bad guy never goes down from a single, perfect shot to the head. It doesn't happen like in the movies.”

Instead of canceling summer plans, Balboni said to simply "be vigilant, pay attention to law enforcement, and urge and demand your government to do everything it can to keep you safe."

Additional Reporting provided by Georeen Tanner.