It's a retailer's worst nightmare: trampling, shoplifting and fighting on the busiest shopping day of the year.
With several high-profile Black Friday incidents in recent years, merchants and shopping centers are on high alert. Security has been significantly increased and retailers have been training sales clerks on how to deal with crowds and protect not only customers, but also employees and merchandise.
"There's going to be double the security in stores on Black Friday morning," said Britt Beemer, chairman of consumer behavior firm America's Research Group. "Any time you give consumers incredible deals, and there are only so many, there's always a chance someone's going to get mad and shovey."
About 97 million shoppers are expected to shop in stores and online on Black Friday, according to the National Retail Federation. An estimated 140 million people will shop during the four-day holiday weekend.
This year is the fifth anniversary of a particularly notorious Black Friday: In 2008, a Wal-Mart worker was trampled to death in New York and two men died after shooting each other at a Toys R Us in Palm Desert, Calif.
Many retailers have devised creative ways to manage hordes of shoppers.
Best Buy, where customers typically begin to line up days before Black Friday, has arranged for its in-house security to get help from local law enforcement, placed taped pathways on the floors to direct shoppers to specific products and handed out numbered tickets to those in line before the doors open.
The electronics chain also held meetings with employees to prepare for the big day.
"We do dry runs and general managers of the stores give very clear directions on what needs to be done," spokesman Jon Sandler said. "It's very buttoned down and we have our GMs direct the troops so there are very clear directions on what's acceptable and what's not. It's a well-run machine."
This year, with stores opening earlier than ever -- many began offering deals on Thanksgiving Day -- retailers hope the staggered start times and longer shopping bonanza will disperse some of the early morning rush on Black Friday.
Wal-Mart this year introduced a new process that it hoped would make shopping easier and improve traffic flow.
The retailer staggered its Black Friday sales events, rolling out deals at 6 p.m. and 8 p.m. Thanksgiving Day, followed by a third discount at 8 a.m. Friday.
For the first time in all stores, the nation's largest retailer handed out wristbands so customers could shop elsewhere in the store while they waited for the most coveted items to get marked down.
Before the 6 p.m. and 8 p.m. sales events, Wal-Mart customers went to a designated line within the store to secure wristbands for certain products. After the events started, customers with wristbands had two hours to come back to the designated line to pick up their product.
At the Wal-Mart in Porter Ranch, Calif., the more than 450 employees scheduled to work on Thanksgiving participated in dozens of dry runs that began more than a month earlier.
Supervisors assigned to each quadrant of the store walked their teams through a variety of practice situations, such as an encounter with a belligerent customer, store manager Fernando Reyes said.
"We practice worst-case scenarios so we're fully prepared in the event that those actually arise," Reyes said. "Some of the new associates in the store have never experienced this type of situation. Regardless of how well you explain it, until you go through a really intense dry run, it's hard to grasp the intensity of this event."
Rival Target conducted additional crowd management training and is providing store-specific maps online and in stores to help shoppers find Black Friday bargains, a company spokeswoman said. The discount chain has also spread its specials throughout the stores to prevent any one area from being flooded with people.
Another change that shoppers might notice this year is the presence of more officers in uniform. In the past, retailers were more likely to opt for undercover security dressed in plainclothes, but these days the presence of uniformed officers "calms everybody down," Beemer said.
The Occupational Safety and Health Administration recently sent letters to major retailers reminding them of the potential hazards involved with large crowds during holiday sales events. The letter included crowd management safety guidelines to be followed in addition to retailers' own procedures.
Among them were on-site trained security personnel or police officers, barricades or rope lines for pedestrians that do not start right in front of the store's entrance, an emergency plan and not blocking exit doors. The agency also encouraged stores to clearly explain entrance procedures to the public.
As retail stores add to their workforces during the holidays, they are also worrying about employee theft and other behind-the-scenes problems.
Many stores purchase crime insurance policies to protect their organizations against theft or forgery committed by employees, said Steve Balmer, product manager for crime at Travelers Insurance. Balmer said such insurance is especially important during the holiday season.
"There is more risk at this time of year, there's more opportunity and there are more people present," Balmer said. "We see it as important for any retailer to be more vigilant about control of merchandise."
Shoppers, too, need to be watchful of their purses and purchases: Travelers said that, on average, more thefts occur on Black Friday than on any other day of the year.