Picketing is a form of protest in which people (called picketers) congregate outside a place of work or location where an event is taking place. Protest expresses relatively overt reaction to events or situations sometimes in favor though more often opposed Employment is a Contract between two parties, one being the employer and the other being the employee. Often, this is done in an attempt to dissuade others from going in ("crossing the picket line"), but it can also be done to draw public attention to a cause. Pickets normally endeavor to be non-violent. Nonviolent resistance (or nonviolent action) is the practice of achieving socio-political goals through Symbolic Protests Civil disobedience, It can have a number of aims, but is generally to put pressure on the party targeted to meet particular demands. This pressure is achieved by harming the business through loss of customers and negative publicity, or by discouraging or preventing workers from entering the site and thereby preventing the business from operating normally.
Picketing is a common tactic used by trade unions during strikes, who will try to prevent dissident members of the union, members of other unions and ununionised workers from working. A trade union or labour union is an organization of workers who have banded together to achieve common goals in key areas such as wages hours and working conditions forming Strike action, often simply called a strike, is a work stoppage caused by the mass refusal by Employees to perform work. Those who cross the picket line and work despite the strike are known pejoratively as scabs. A strikebreaker (also called scab or knobstick) is a person who works despite an ongoing strike.
A mass picket is an attempt to bring as many people as possible to a picket line, in order to demonstrate support for the cause. It is primarily used when only one workplace is being picketed, or for a symbolically or practically important workplace. Due to the numbers involved, a mass picket may turn into a blockade. A blockade is any effort to prevent supplies Troops information or aid from reaching an opposing force
Secondary picketing is where people picket locations that are not directly connected to the issue of protest. This would include retail stores that sell products by the company being picketed against, and the private homes of the company's management. Secondary pickets often do not have the same civil law protection as primary pickets.
Another tactic is to organize highly mobile pickets who can turn up at any of a company's locations on short notice. These flying pickets are particularly effective against multifacility businesses which could otherwise pursue legal prior restraint and shift operations among facilities if the location of the picket were known with certainty ahead of time. Prior restraint is a Legal term referring to a Government 's actions that prevent materials from being published
Picketing is also used by pressure groups across the political spectrum. An interest group (also advocacy group, lobby group, pressure group or special interest group) is an organized collection of people who seek Picketing has also been employed for religious purposes such as the Westboro Baptist Church who picket a variety of stores or events that they consider to be sinful. The Westboro Baptist Church (WBC is a church headed by Fred Phelps and based in Topeka Kansas, United States.
Disruptive picketing is where pickets use force, or the threat of force, or physical obstruction, to injure or intimidate or otherwise interfere with either staff, service users, or customers. 
In the US, disruptive picketing of abortion providers is a common form of pro-life protest: over thirteen thousand incidents were reported in 2005. Overview See also Ethical aspects of abortion Pro-life individuals generally believe that human life should be valued either from conception or Implantation 
Picketing, as long as it does not cause obstruction to a highway or intimidation, is legal in many countries and in line with freedom of assembly laws, though many countries do have restrictions on the use of picketing. Freedom of assembly, sometimes used interchangeably with the Freedom of association, is the Individual right to come together with other individuals and collectively
In the UK the Trade Union and Labour Relations (Consolidation) Act 1992 gives protection under civil law for pickets who are acting in connection with an industrial dispute at or near their workplace who are using their picketing to peacefully obtain or communicate information or peacefully persuading any person to work or abstain from working. The Trade Union and Labour Relations (Consolidation Act 1992 is a UK Act of Parliament which regulates the operation of Trade unions and Industrial action However, many employers have recently taken to gaining injunctions to limit the effect of picketing outside their work place. An injunction is an Equitable remedy in the form of a Court order, whereby a party is required to do or interact with in certain ways all right or to refrain from The granting of injunctions tends to be based on the accusation of intimidation or in general on non-peaceful behaviour and the claim that numbers of the pickers are not from the affected work place.  Historically, picketing was banned by a Liberal government in the Criminal Law Amendment Act 1871 but then decriminalised by a Conservative government with the Conspiracy and Protection of Property Act 1875. The Liberal Party was one of the two major British political parties from the early 19th century until the rise of the Labour Party in the 1920s and a third party The Criminal Law Amendment Act 1871 ( 34 & 35 Victoria c 32) is an Act of the Parliament of the United Kingdom passed by W The Conservative Party (officially the Conservative and Unionist Party) is a Political party in the United Kingdom. The Conspiracy and Protection of Property Act 1875 is an Act of the Parliament of the United Kingdom relating to Labour relations, which together with the 
In the US any strike activity was hard to organise in the early 1900s, however picketing became more common after the Norris-LaGuardia Act of 1932, which limited the ability of employers to gain injunctions to stop strikes, and further legislation which supported the right to organise for the unions. The Norris-La Guardia Act (also known as the Anti-Injunction Bill) of 1932 was a United States federal law that made Yellow-dog contracts Year 1932 ( MCMXXXII) was a Leap year starting on Friday of the Gregorian calendar. Mass picketing and secondary picketing was however outlawed by the The Taft-Hartley Labor Act (1947).  Some kinds of pickets are constitutionally protected. Freedom of speech in the United States is protected by the First Amendment to the United States Constitution and by many state constitutions