A promotional stunt for LG smartphone vouchers led to 20 injuries in Seoul, South Korea on Friday. The incident sent seven of the 20 to the hospital, which led LG to cancel the rest of its promotional event series. When LG released 100 helium balloons, each with a free G2 smartphone voucher attached, people came armed with BB guns, butterfly nets, and sticks rigged with knives.

The new smartphone was released in New York last week after weeks of build-up on social media websites like Facebook and Twitter. The handset sells for 950,000 KRW in South Korea ($851) and is scheduled for global release with more than 130 carriers in the coming weeks.

The anticipation of the new gadget incited people to come prepared with weapons; one person was seen carrying a pointed staff. The event, which was called “G in the Cloud,” took place in an outdoor park located in Seoul. Due to the high number of people, it is unclear if injuries were incurred by the weapons present or if a stampede sent them to the hospital.

“LG Electronics deeply regrets that a number of Korean participants were injured during an outdoor promotional event in Seoul, Korea,” the firm’s released statement said. “LG is investigating the incident to ensure that such an occurrence can be avoided in the future.”

The Psychology Behind Flocking For Free Stuff

There can be danger in promotional events, especially when things are free or when there's a good sale. For instance, there have been many injuries and deaths every year from tramplings on infamous Black Friday sale's events. There is a psychology behind people's impulses into buying so readily, and one of the main triggers is time-pressured sales, according to Art Markman of Psychology Today.

“Retailers are enticing people into stores with the promise of great deals on products,” Markman said. “The retailer offers discounts on products and suggests that there discounts will not be around for long. The crowd in the store gives the impression that you have to act quickly. These factors push people away from a deliberation mindset and toward an action mindset.”

Another aspect of the craze is when retailers offer incredible deals on big-ticket items, such as free smartphones. The limited quantities inspire long lines, impatience, and desperation for the low-supply item in high demand. This simple economic principle is what drives promotional events and what also makes them so dangerous.

According to Sang-Eun Byun, an assistant professor of consumer affairs at Auburn University, the competition drives people to do drastic things and “creates what’s called hedonic shopping value, or a sense of enjoyment from the mere process of buying goods.”

People love saving money, and the competitive nature can drive people into deriving great pleasure from winning a prize, such as a vouchered balloon. But competitive shopping environments, even one where there is no exchange of money, can make people prone to increased misbehavior.

“Having a vision of how your bargain-hunting triumph will play out can apparently make you more aggressive when other bargain hunters get in your way,” according to psychologist Jane Body Thomas’ research on Black Friday consumer psychology. “Your dashed hopes for a successful ‘hunt’ can lead to negative behavior.”