Why Super Bowl 50 will be most highly-guarded sports event in US history

Super Bowl 50 is likely to be one of the most highly-guarded sporting events in US history, law enforcement officials say, as recent terrorist attacks in Paris and San Bernardino, Calif., have motivated federal agencies to take extra precautions while insisting that there is no credible or significant threat to the game this Sunday.

One million people are expected to descend on the San Francisco Bay Area this week – the game will be played at Levi's Stadium in Santa Clara, 50 miles southeast of San Francisco – and security officials say they will have a tough task balancing civil liberties and protecting spectators from the kind of lone-wolf attacks that caused devastation in Paris and San Bernardino.

November's series of coordinated attacks across the French capital, linked to the terrorist group known as the Islamic State, included bombings near entrances to the national stadium during a soccer game. A couple sympathetic to the Islamic State also carried out the December mass shooting in San Bernardino. 

"This is a high-profile target," David Johnson, special agent in charge of the FBI's San Francisco field office, told Reuters. "A terrorist group would receive a great deal of publicity [if they attack the Super Bowl], which is what they are looking for."

The Department of Homeland Security classifies each Super Bowl a special event assignment rating (SEAR) 1 event, the second highest possible classification, only below events like presidential inaugurations and summits of world leaders. 

A no-fly zone will be effectively imposed over the stadium and its environs, according to two federal officials, meaning most, if not all, air traffic will be limited to official aircraft. The US Coast Guard will also create a maritime exclusion zone in the creek around the stadium, officials said.

The DHS will also be screening all cargo going into the stadium with a giant X-ray machine, department spokeswoman Marsha Catron said.

But officials said the most vulnerable "targets of opportunity" will be outside, not inside, the stadium, and a fear of lone wolf attacks similar to the San Bernardino shootings will see heavy surveillance – both human and mechanical – outside the stadium.

The San Jose Mercury News reported in November that event’s sprawling security apparatus will stretch from the stadium to San Francisco itself, and is designed to protect "a region pockmarked with less-secure 'soft targets' such as malls, transit hubs and restaurants."

Yet security officials have acknowledged the challenges they face in preventing attacks in an area this size without infringing on Constitutional rights. They are also preparing for possible street protests in the area this week.

"There is a delicate balance and we don't want to infringe upon anyone’s Constitutional rights," Santa Clara Police Lieutenant Kurt Clarke told Reuters.

The Transportation Security Administration will be deploying "behavior detection officers" to watch over crowds, especially at busy locations like train stations, according to Ms. Catron.

A host of surveillance technologies will also be deployed in the Bay Area this week, April Glaser reported for Wired, technologies that will track everything from your car and phone, to your face and body.

"If all this surveillance in the name of security makes you uncomfortable and you'd rather not have your face, car, and cell phone activity tracked across the Bay Area, you have only one option: Don't go anywhere near the big game," wrote Ms. Glaser.

This report contains material from Reuters.