Picketing is a form of protest where people gather outside a place of work or location where an event is taking place to draw public attention to a cause or to put pressure on the party targeted to meet particular demands or cease operations. Picketers normally endeavor to be non-violent. It can have a number of aims, but is generally to harm the business through loss of customers and negative publicity, or by discouraging or preventing workers or customers 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 non-unionized workers from working. Those who cross the picket line and work despite the strike are known pejoratively as scabs. There are two primary types of picketing, which are defined by where the picketing takes place. Primary picketing takes place at the workplace of the employer with whom the picketers have a dispute, while secondary picketing takes place at the workplace of an employer other than the primary employer. Picketing is constitutionally protected as an exercise of freedom of speech, but it is subject to reasonable regulation. If you want to join a picket line, you should ask your union for advice. You can lawfully join a picket line as long as the picketing is connected to a trade dispute which you are involved in, carried out at or near your own workplace, and carried out peacefully.