A map of Texas’s “breastaurants.” The state hosts more Twin Peaks outlets than any other, and is second only to Florida in its number of Hooters chains. (Source: GoogleMaps)

As horrifying images of the bike gang shootout emerged from Waco, Tex., on Sunday, journalists had to tackle a question: Why had bikers chosen to congregate at a restaurant called Twin Peaks before what one official called “one of the worst gun fights we’ve ever had in the city limits”? It turned out Twin Peaks is a Hooters knock-off, using sex to sell booze and food in what’s popularly known as a “breastaurant.”

[Waco police: Twin Peaks “has some answering to do" following violence]

“Twin Peaks, headquartered in Dallas, is a casual dining chain with dozens of locations nationwide that employs a largely female staff scantily clad in plaid shirts and mini shorts,” The Washington Post’s Peter Holley reported. “The ‘breastaurant’ chain’s CEO, Randy DeWitt, calls his female employees ‘weapons of mass distraction’ and once told Bloomberg News: ‘Hooters just wasn’t racy enough.’ ”

After the shooting, Twin Peaks offered sympathy for those killed and injured, but blamed the incident on a franchise run amok.

“We are in the people business and the safety of the employees and guests in our restaurants is priority one,” the company wrote in a statement posted to its Facebook page. “Unfortunately the management team of the franchised restaurant in Waco chose to ignore the warnings and advice from both the police and our company, and did not uphold the high security standards we have in place to ensure everyone is safe at our restaurants. We cannot tolerate the actions of this relatively new franchisee and have revoked their franchise agreement effectively immediately.”

[How the Bandidos became one of the world’s most feared biker gangs]

Yet, at Twin Peaks restaurants in Texas and around the country, what are called “bike nights” were regularly on the calendar before this week’s shooting — the same kinds of events that the Waco location was asked to discontinue.

“Get revved up and ready to go at Twin Peaks bike night,” reads a cached version of an April events page for a Twin Peaks in Oklahoma City.

This bike night was held last year in Henderson, Nev. This bike night was held last week in Lincoln, Neb. And this Twin Peaks in Plano, Tex., used to have bike night every Thursday. After last week’s incident, the bike night was put on hold “pending corporate,” according to an employee who answered the phone at the franchise. (The company was not immediately available for comment.)

So: What happens at bike night? Certainly, there’s not a gang shootout every week at every outlet. Most, it seems, are harmless mini-conventions for gearheads — except, maybe, for the staff’s choice of attire.

“On my last night in Concord, I was taken to Twin Peaks for dinner,” one enthusiastic Trip Advisor reviewer said of a trip to a restaurant in North Carolina. “It was the night when all the motorcycle riders turn out to show off their bikes and to get together and have some fun. It’s also the night when the waitresses dress up as school girls. The place had a fabulous atmosphere and everyone seemed to have a great night.”

The debut of a Twin Peaks in Omaha in 2011 even featured a bike night.

“Meanwhile a Grand Opening Celebration is scheduled for May 5, Cinco De Mayo,” according to a news release. “That will also kick off Thursday ‘Bike Nights’ at the restaurant.”

The franchisee was enthusiastic.

“We’ll mark off part of the parking lot for the bikes, have a band and put on a big event,” he said. “It will be great.”

Bike night at a Hooters in Pembroke Pines, Fla.

But whatever happens at bike night, the great abundance of breastaurants in Texas — many clustered around the I-35 corridor and near Dallas, Twin Peaks’s headquarters — ensure that motorcycle enthusiasts from Brownsville to Norman, Okla., had their opportunity to “get revved up.” Most Twin Peaks locations are in Texas; Hooters has been known to host the odd bike night as well — including this one in Rockville, Md., that has bike night every Thursday.

Florida, with 78 outlets, is a Hooters heaven. Texas, with 52, comes in second, according to the Web site Menuism.

Sunday’s shootout aside, bike nights do not always end well. Indeed, a bike night ongoing at a Hooters in New Castle, Del., for 12 years was canceled after a fight broke out in 2013. The spat, which came to fisticuffs, was between about 50 current and former members of the Pagans motorcycle club.

Why was bike night called off?

Manager Steve Rudolph “didn’t want to put employees at harm,” as he told WDEL.