Pickets may further disrupt an employer's business because one union member, such as a truck driver, may refuse to cross the other's picket line.

Pickets

Individuals or groups that stand or march outside a place of work to protest or to discourage others from entering, often as part of a strike.

Picket Line

A boundary established by workers on strike, especially in front of a workplace, to publicize their cause and to dissuade or prevent others from entering the premises.