Bouncers are often required where crowd size, clientele or alcohol consumption may make arguments or fights a possibility, or where the threat or presence of criminal gang activity or violence is high.

[5][failed verification] In the 1990s and 2000s, increased awareness of the risks of lawsuits and criminal charges have led many bars and venues to train their bouncers to use communication and conflict resolution skills before, or rather than, resorting to brute force against troublemakers.

Historical references also suggest that the 'door supervisor' function of guarding a place and selecting who can have entry to it (the stereotypical task of the modern bouncer) could at times be an honorific and evolve into a relatively important position.

[9] Plautus, in his play Bacchides (written approximately 194–184 BC), mentions a "large and powerful" doorman / bouncer as a threat to get an unwelcome visitor to leave.

[11] Within Buddhist lore, the Nio, the twin guardian statues who decorate the entrances of temples, dojos, and various places related with religious importance, are believed to be the embodiment of wrathful deity bodhisattvas such as Vajrapani, Mahasthamaprapta, Vajrasattva, Acala, or various figures within Buddhist legend who accompanied Gautama Buddha during his journeys to spread his teachings to protect him and aid in cases needing justified force.

During the late 19th and early 20th centuries, US saloon-keepers and brothel madams hired bouncers to remove troublesome, violent, or dead-drunk patrons, and to protect the saloon girls and prostitutes.

In Chapter XIV, entitled "Bounced", a boy is thrown out of a restaurant because he has no money to pay for his meal: "Here, Peter, you waited on this young man, didn't you?"

This proceeding was followed by derisive laughter from the other waiters who had gathered near the door, and it was echoed by two street urchins outside, who witnessed Sam's ignominious exit from the restaurant.

Sam staggered from the force of the bouncing, and felt disgraced and humiliated to think that the waiter who had been so respectful and attentive should have inflicted upon him such an indignity, which he had no power to resent.An 1883 newspaper article stated that "'The Bouncer' is merely the English 'chucker out'.

For security, "somewhere in every parlor of the house there was always a bouncer, a giant of a man who stayed sober to handle any customer who got too rough with one of the girls or didn't want to pay his bill."

"[13] In Wisconsin's lumberjack days, bouncers would physically remove drinkers who were too drunk to keep buying drinks, and thus free up space in the bar for new patrons.

The slang term 'snake-room' was used to describe a "...room off a saloon, usually two or three steps down, into which a bar-keeper or the bouncer could slide drunk lumber-jacks head first through swinging doors from the bar-room.

"[16] In the 1880s and 1890s, bouncers were used to maintain order in "The Gut", the roughest part of New York City's Coney Island, which was filled with "ramshackle groups of wooden shanties", bars, cabarets, fleabag hotels and brothels.

Huge bouncers patrolled these venues of vice and "roughly ejected anyone who violated the loose rules of decorum" by engaging in pick-pocketing, jewelry thieving, or bloody fights.

The Oasis club, operated by Max Cohen, hired "...a lady bouncer by the name of Mickey Steele, a six-foot acrobat from the Pennsylvania coal fields.

Hong Kong police have noted that due to the letter of the law, they sometimes had to charge the bouncer for illegally extorting the women when the usually expected dominance situation between the sex worker and her "protector" was in fact reversed.

This may be encouraged by management adherence to a repressive model of supervision of patrons ("if they play up, thump 'em"), which in fact does not reduce trouble, and exacerbates an already hostile and aggressive situation.

[35] The study has, however, attracted some criticism due to the fact that the researcher, while fulfilling his duties as a bouncer and being required to set aside his academic distance, would have been at risk of losing objectivity—though it was accepted that this quandary might be difficult to resolve.

Various other elements, such as body language or physical looks (muscles, shaved heads) were also described as often expected for entry into bouncing—being part of the symbolic 'narratives of intimidation' that set bouncers apart in their work environment.

[37] Bouncers answer questions about club policies and procedures while controlling crowds (by asking people not to block entrances, exits, stairwells, and other high-traffic areas).

[37] An ability to judge and communicate well with people will reduce the need for physical intervention, while a steady personality will prevent the bouncer from being easily provoked by customers.

The decision to turn certain customers away at the door because of too casual clothing (face control) is for example often based on the perception that the person will be more willing to fight (compared to someone dressed in expensive attire).

In Australia, the number of complaints and lawsuits against venues due to the behaviour of their bouncers has been credited with turning many establishments to using former police officers to head their in-house security, instead of hiring private firms.

[54] In Australia, for example, women comprise almost 20% of the security industry and increasingly work the door as well, using "a smile, chat and a friendly but firm demeanor" to resolve tense situations.

[55] Nearly one in nine of Britain's nightclub bouncers are also women, with the UK's 2003 Licensing Act giving the authorities "discretionary power to withhold a venue's licence if it does not employ female door staff".

In some countries or regions, bouncers may be required to have extra skills or special licenses and certification for first aid, alcohol distribution, crowd control, or fire safety.

[63] Nova Scotia passed a law in 2010 requiring bouncers to be trained and licensed, but the province has never adopted detailed regulations and proclaimed the legislation into effect.

The course contains both theoretical and practical training and exams and can only be entered if the subject does not have a criminal record, which will be checked by a screening by Police departments in the region where the company is located.

These security officers have powers of citizen's arrest and to verbally dismiss, physically remove, or detain those who disturb or pose an immediate threat to public order or safety, by using a reasonable amount of force.

When foreign ants venture close, the force of the mandibles is sufficient to throw back the intruder for a significant distance, a defense behaviour which is thought to also protect the guard against physical or chemical injury that it might sustain in more direct battle.