A company selects certain items to sell at amazingly low prices to entice shoppers into their store on Black Friday because once in the building, it is likely that most of those shoppers will purchase additional items. There are always the bargain hunters who come in specifically for that single item but they are the exception. Most stay and shop.
There is not an unlimited supply of these items. There are only a certain number that can be/actually are physically manufactured. If there is a limit posted in the ad, that means that there is a finite number available which must be divided between the total number of stores to meet the minimum quantity available. Consider Wal Mart.
# United States: 4,227 total units
* Wal-Mart discount stores (914)
* Supercenters (2,576)
* Sam's Clubs (594)
* Neighborhood Markets (143)
The first two share the same advertising. That means roughly 3500 stores have the aforementioned "25" items. Granted, regional advertising means that the entire chain does not have to feature the same item.
Look at the country of origin label on the item. Chances are, it comes from overseas. That means a decision about what will be currently desirable must be made nearly a year in advance. In the case of electronics such as computers, TV's, and personal items like Ipods, that's a lifetime since technology can leapfrog past your carefully researched special buy. Then it needs to be manufactured and shipped in those big containers which often have to sit for weeks to clear customs. That's why rainchecks have no value. There is not enough time between Thanksgiving to order and receive the item from overseas. No one likes to give or get a raincheck for Christmas and they don't have the money or desire to come back to the store in March of the next year when it finally arrives.
Then there is the 'Open to Buy' to consider. Buyers have a budget they must live within. They don't have unlimited funds to use on a low or no profit item because they still need to buy all the other items in the store that it must sell to stay profitable and keep its doors open.
The pressure to find the perfect item that will make people choose your store over another is massive. A mistake will mean stacks of boxes containing items no one wants at any price. You can't stay open if the shoppers won't come through your doors and stay a while.
The store in question had security but how much is enough. No one knows when a crowd will get so rowdy they will trample another human to be first in line for a TV. How much respect is there for private security vs real police? If the local cops are busy sitting on a crowd outside of Wal Mart, who's watching the crowd outside of Best Buy, Sears, and everyone else?
Maybe the National Guard should be mobilized on BF to cover every ad that comes in the holiday newspaper?
Of course, if every state followed the Texas example, there crowds might be a lot calmer since it has laws permitting you to carry and conceal your weapon. You are less likely to pick a fight or push against the person in front of you if you don't know if they are strapped or not. Wouldn't that be a joyous experience!